View Filing Data

Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	Dec. 31, 2011	Mar. 13, 2012	Jun. 30, 2011
Entity Information
Entity Registrant Name	NATURAL GAS SERVICES GROUP INC
Entity Central Index Key	0001084991
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2011
Document Fiscal Year Focus	2011
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding		12,296,499
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 197,580,224

Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2011	Dec. 31, 2010
Current Assets:
Cash and cash equivalents	$ 16,390	$ 19,137
Trade accounts receivable, net of allowance for doubtful accounts of $296 and $171 as of December 31, 2011 and December 31, 2010, respectively	5,679	5,279
Inventory, net of allowance for obsolescence of $486 and $250 as of December 31, 2011 and December 31, 2010, respectively	26,965	21,489
Prepaid income taxes	109	2,103
Prepaid expenses and other	360	330
Total current assets	49,503	48,338
Rental equipment, net of accumulated depreciation of $56,623 and $44,245 as of December 31, 2011 and December 31, 2010, respectively	142,473	120,755
Property and equipment, net of accumulated depreciation of $7,786 and $7,899 as of December 31, 2011 and December 31, 2010, respectively	7,839	7,149
Goodwill, net of accumulated amortization of $325, both periods	10,039	10,039
Intangibles, net of accumulated amortization of $1,936 and $1,757 as of December 31, 2011 and December 31, 2010, respectively	2,282	2,461
Other assets	28	27
Total assets	212,164	188,769
Current Liabilities:
Current portion of long-term debt	0	0
Line of credit	0	2,000
Accounts payable	3,730	3,364
Accrued liabilities	3,644	2,151
Current income tax liability	75	0
Deferred income	4,863	389
Total current liabilities	12,312	7,904
Line of credit, noncurrent portion	1,017	0
Deferred income tax payable	36,769	29,746
Other long-term liabilities	524	528
Total liabilities	50,622	38,178
Stockholders’ Equity:
Preferred stock, 5,000 shares authorized, no shares issued or outstanding	0	0
Common stock, 30,000 shares authorized, par value $0.01; 12,179 and 12,148 shares issued and outstanding as of December 31, 2011 and December 31, 2010, respectively	122	122
Additional paid-in capital	87,225	86,034
Retained earnings	74,195	64,435
Total stockholders' equity	161,542	150,591
Liabilities and Stockholders' Equity	$ 212,164	$ 188,769

Balance Sheets (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Dec. 31, 2011	Dec. 31, 2010
Current Assets:
Allowance for doubtful accounts	$ 296	$ 171
Allowance for inventory obsolescence	486	250
Noncurrent Assets:
Accumulated depreciation, rental equipment	56,623	44,245
Accumulated depreciation, property and equipment	7,786	7,899
Accumulated amortization, goodwill	325	325
Accumulated amortization, intangibles	$ 1,936	$ 1,757
Stockholders' Equity:
Preferred stock, shares authorized	5,000	5,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	30,000	30,000
Common stock, shares issued	12,179	12,148
Common stock, shares outstanding	12,179	12,148

Statements of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Revenue:
Sales, net	$ 15,419	$ 12,370	$ 21,657
Rental income	48,619	40,670	45,146
Service and maintenance income	1,120	868	993
Total revenue	65,158	53,908	67,796
Operating costs and expenses:
Cost of sales, exclusive of depreciation stated separately below	9,194	8,010	14,880
Cost of rentals, exclusive of depreciation stated separately below	20,742	16,205	16,600
Cost of service and maintenance, exclusive of depreciation stated separately below	458	535	677
Selling, general, and administrative expense	5,910	5,867	6,190
Depreciation and amortization	13,994	11,927	11,686
Total operating costs and expenses	50,298	42,544	50,033
Operating income	14,860	11,364	17,763
Other income (expense):
Interest expense	(55)	(194)	(606)
Other income	824	130	70
Total other income (expense)	769	(64)	(536)
Income before provision for income taxes	15,629	11,300	17,227
Current income taxes	75	24	1,756
Deferred taxes	5,794	4,248	4,456
Total income tax expense	5,869	4,272	6,212
Net income	$ 9,760	$ 7,028	$ 11,015
Earnings per share:
Basic	$ 0.80	$ 0.58	$ 0.91
Diluted	$ 0.80	$ 0.58	$ 0.91
Weighted average shares outstanding:
Basic	12,148	12,108	12,096
Diluted	12,250	12,210	12,118

Statement of Stockholders' Equity - USD ($) shares in Thousands	Total	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]
Preferred Stock, Shares Outstanding at Dec. 31, 2008		0
Stockholders' Equity Attributable to Parent at Dec. 31, 2008	$ 130,450,000	$ 0	$ 121,000	$ 83,937,000	$ 46,392,000
Common Stock, Shares, Outstanding at Dec. 31, 2008			12,094
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of common stock options and warrants			7
Exercise of common stock options and warrants, value	49,000		$ 0	49,000	0
Compensation expense on issuance of common stock options, value	584,000			584,000	0
Net Income (Loss) Attributable to Parent	11,015,000		$ 0	0	11,015,000
Preferred Stock, Shares Outstanding, Ending Balance at Dec. 31, 2009		0
Common Stock, Shares, Outstanding, Ending Balance at Dec. 31, 2009			12,101
Stockholders' Equity Attributable to Parent, Ending Balance at Dec. 31, 2009	142,098,000	$ 0	$ 121,000	84,570,000	57,407,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of common stock options and warrants			46
Exercise of common stock options and warrants, value	407,000		$ 1,000	406,000	0
Compensation expense on issuance of common stock options, value	804,000			804,000	0
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures			1
Issuance of restricted stock	0		$ 0	0	0
Compensation expense on issuance of restricted common stock	254,000		0	254,000	0
Net Income (Loss) Attributable to Parent	$ 7,028,000		$ 0	0	7,028,000
Preferred Stock, Shares Outstanding, Ending Balance at Dec. 31, 2010	0	0
Common Stock, Shares, Outstanding, Ending Balance at Dec. 31, 2010	12,148		12,148
Stockholders' Equity Attributable to Parent, Ending Balance at Dec. 31, 2010	$ 150,591,000	$ 0	$ 122,000	86,034,000	64,435,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of common stock options and warrants		0	18
Exercise of common stock options and warrants, value	123,000	$ 0	$ 0	123,000	0
Compensation expense on issuance of common stock options, value	461,000			461,000	0
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures		0	13
Issuance of restricted stock	0	$ 0	$ 0	0	0
Compensation expense on issuance of restricted common stock	607,000	0	0	607,000	0
Net Income (Loss) Attributable to Parent	$ 9,760,000	$ 0	$ 0	0	9,760,000
Preferred Stock, Shares Outstanding, Ending Balance at Dec. 31, 2011	0	0
Common Stock, Shares, Outstanding, Ending Balance at Dec. 31, 2011	12,179		12,179
Stockholders' Equity Attributable to Parent, Ending Balance at Dec. 31, 2011	$ 161,542,000	$ 0	$ 122,000	$ 87,225,000	$ 74,195,000

Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
Statements of Cash Flows - USD ($) $ in Thousands	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 9,760	$ 7,028	$ 11,015
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	13,994	11,927	11,686
Deferred taxes	5,869	4,248	4,456
Stock options and restricted stock expense	1,068	1,058	584
Gain on disposal of assets	(717)	(46)	(51)
Changes in current assets and liabilities:
Trade accounts receivables, net	(400)	2,035	4,007
Inventory, net	(5,476)	2,773	9,008
Prepaid income taxes and prepaid expenses	1,964	(598)	(1,504)
Accounts payable and accrued liabilities	1,859	1,791	(8,673)
Current income tax liability	1,229	(1,708)	1,598
Deferred income	4,474	299	52
Other	(1)	(9)	0
NET CASH PROVIDED BY OPERATING ACTIVITIES	33,623	28,798	32,178
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of property and equipment	(36,525)	(21,908)	(9,542)
Redemption of short-term investments	0	0	2,300
Proceeds from sale of property and equipment	1,019	47	143
NET CASH USED IN INVESTING ACTIVITIES	(35,506)	(21,861)	(7,099)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from line of credit	0	2,000	500
Repayments of long-term debt	0	(6,194)	(3,378)
Repayments of line of credit	(983)	(7,000)	(500)
Proceeds from other long term liabilities, net	(4)	(30)	118
Proceeds from exercise of stock options	123	407	49
NET CASH PROVIDED BY FINANCING ACTIVITIES	(864)	(10,817)	(3,211)
NET CHANGE IN CASH	(2,747)	(3,880)	21,868
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	19,137	23,017	1,149
CASH AND CASH EQUIVALENTS AT END OF PERIOD	16,390	19,137	23,017
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION:
Interest paid	61	238	613
Income taxes paid	130	2,204	1,477
NON-CASH TRANSACTIONS
Transfer of rental equipment to inventory	$ 0	$ 225	$ 1,114

Basis of Presentation and Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2011

Basis of Presentation and Summary of Significant Accounting Policies [Abstract]

Basis of Presentation and Significant Accounting Policies [Text Block]

Summary of Significant Accounting Policies

Organization and Principles of Consolidation

These notes apply to the financial statements of Natural Gas Services Group, Inc. (the "Company", “NGSG”, "Natural Gas Services Group", "we" or "our") (a Colorado corporation). Natural Gas Services Group, Inc. was formed on December 17, 1998 for the purposes of combining the operations of certain manufacturing, service and leasing entities.

Nature of Operations

Natural Gas Services Group, Inc. is a leading provider of small to medium horsepower compression equipment to the natural gas industry. We focus primarily on the non-conventional natural gas production business in the United States (such as coal bed methane, gas shale and tight gas). We manufacture, fabricate and rent natural gas compressors that enhance the production of natural gas wells. NGSG provides maintenance services for its natural gas compressors. In addition, we sell custom fabricated natural gas compressors to meet customer specifications dictated by well pressures, production characteristics and particular applications. We also manufacture and sell flare systems for oil and natural gas plant and production facilities.

Use of Estimates

The preparation of our financial statements in conformity with accounting principles generally accepted in the United States of America requires our management to make estimates and assumptions that affect the amounts reported in these financial statements and accompanying notes. Actual results could differ from those estimates. Significant estimates include the valuation of identifiable intangible assets and goodwill acquired in acquisitions, bad debt allowance and the allowance for inventory obsolescence. It is at least reasonably possible these estimates could be revised in the near term and the revisions could be material.

Cash Equivalents

For purposes of reporting cash flows, we consider all short-term investments with an original maturity of three months or less to be cash equivalents.

Accounts Receivable

Our trade receivables consist of customer obligations for the sale of compressors and flare systems due under normal trade terms, and operating leases for the use of our natural gas compressors. The receivables are not collateralized except as provided for under lease agreements. However, we require deposits of as much as 50% for large custom contracts. We extend credit based on management's assessment of the customer's financial condition, receivable aging, customer disputes and general business and economic conditions. Management believes the allowance for doubtful accounts for trade receivables of $296,000 and $171,000 at December 31, 2011 and 2010, respectively, is adequate.

Revenue Recognition

Revenue from the sales of custom and fabricated compressors, and flare systems is recognized when title passes to the customer, the customer assumes risks and rewards of ownership, collectability is reasonably assured and delivery occurs as directed by our customer. Exchange and rebuilt compressor revenue is recognized when both the replacement compressor has been delivered and the rebuild assessment has been completed. Revenue from compressor service and retrofitting services is recognized upon providing services to the customer. Maintenance agreement revenue is recognized as services are rendered. Rental revenue is recognized over the terms of the respective rental agreements. Deferred income represents payments received before a product is shipped. Revenue from the sale of rental units is included in sales revenue when equipment is shipped or title is transferred to the customer.

Description of Rental Arrangements

Our rental operations principally consist of the rental of natural gas compressor packages and flare stacks. These arrangements are classified as operating leases. See Note 2.

Major Customers and Concentration of Credit Risk

Sales and rental income to EOG Resources, Inc. ("EOG") and Devon Energy Production, Inc. ("Devon") in 2011 amounted to 17% and 16% of revenue, respectively. Sales and rental income to Devon in 2010 amounted to 19% of revenue. Sales and rental income to XTO Energy, Inc. and Devon in 2009 each amounted to 21% of revenue. No other single customer accounted for more than 10% of our revenues in 2011, 2010 or 2009. EOG, Devon, and Linn Operating amounted to 39%, 20%, and 11% of our accounts receivable as of December 31, 2011, respectively. BP and Devon amounted to 19% and 10%, respectively, of our accounts receivable as of December 31, 2010. No other customers amounted to more than 10% of our accounts receivable as of December 31, 2010 and 2011.

Inventory

Inventory is valued at the lower of cost or market. The cost of inventories is determined by the weighted average method. A reserve is recorded against inventory balances for estimated obsolescence. This reserve is based on specific identification and historical experience and totaled $486,000 and $250,000 at December 31, 2011 and 2010, respectively. There were no new completed compressor units at December 31, 2011 or at December 31, 2010 available for sale or for use in our rental fleet. At December 31, 2011 and 2010, respectively, inventory consisted of the following (in thousands):



	2011		2010
Raw materials	$	20,364	$	17,770
Finished goods	—		—
Work in process	6,601		3,719
	$	26,965	$	21,489

Property and Equipment

Property and equipment is recorded at cost less accumulated depreciation. Depreciation is computed using the straight-line method over the estimated useful lives of the assets, which range from three to forty years. Rental equipment has an estimated useful life of fifteen years.

Gains and losses resulting from sales and dispositions of property and equipment are included in current operations. Maintenance and repairs are charged to operations as incurred.

Goodwill

Goodwill represents the cost in excess of fair value of the identifiable net assets acquired in three acquisitions. Goodwill is tested for impairment annually or whenever events indicate impairment may have occurred. The annual goodwill impairment test is performed internally in the fourth quarter of each year.

Intangibles

At December 31, 2011, NGSG had intangible assets with a gross carrying value of $4.2 million, which relate to developed technology, acquired customer contracts, distribution agreements and non-compete agreements. The carrying amount net of accumulated amortization at December 31, 2011 and 2010 was $2.3 million and $2.5 million respectively. Intangible assets are amortized on a straight-line basis with useful lives ranging from 5 to 20 years, with a weighted average remaining life of approximately fourteen years as of December 31, 2011. Amortization expense recognized in each of the years ending December 31, 2011, 2010, and 2009 was $179,000, $260,000 and $299,000 respectively. In addition, NGSG has an intangible asset with a gross carrying value of $654,000 at December 31, 2011 related to the trade name of SCS which was acquired in our acquisition of Screw Compression Systems in January 2005. This asset is not being amortized as it has been deemed to have an indefinite life.

The following table represents estimated future amortization expense for the years ending December 31, (in thousands).



2012	$	125
2013	125
2014	125
2015	125
2016	125
Thereafter	1,003
	$	1,628

Our policy is to periodically review intangibles for impairment through an assessment of the estimated future cash flows related to such assets. In the event that assets are found to be carried at amounts in excess of estimated undiscounted future cash flows, then the assets will be adjusted for impairment to a level commensurate with a discounted cash flow analysis of the underlying assets. Based upon our most recent analysis, we believe no impairment of intangible assets exists as of December 31, 2011.

Warranty

We accrue amounts for estimated warranty claims based upon current and historical product warranty costs and any other related information known. The warranty reserve was at $158,000 for both December 31, 2011 and 2010.

Financial Instruments and Concentrations of Credit Risk

Management believes that the fair value of our cash and cash equivalents, trade receivables, accounts payable and line of credit at December 31, 2011 and 2010 approximate their carrying values due to the short-term nature of the instruments or the use of prevailing market interest rates. We invest our cash primarily in deposits and money market funds with commercial banks. At times, cash balances at banks and financial institutions may exceed federally insured amounts.

Other Income

Other income at 2011 was $0.8 million and is primarily due to a gain from the sale of our former headquarters during the first quarter of 2011.

Per Share Data

Basic earnings per common share is computed using the weighted average number of common shares outstanding during the period. Diluted earnings per common share is computed using the weighted average number of common stock and common stock equivalent shares outstanding during the period. There were no an anti-dilutive securities in 2011, 2010, and 2009.

The following table sets forth the computation of basic and diluted earnings per share (in thousands, except per share amounts):



	Year Ended December 31,
	2011		2010		2009
Numerator:
Net income	$	9,760	$	7,028	$	11,015
Denominator for basic net income per common share:
Weighted average common shares outstanding	12,148		12,108		12,096
Denominator for diluted net income per share:
Weighted average common shares outstanding	12,148		12,108		12,096
Dilutive effect of stock options and restricted shares	102		102		22
Diluted weighted average shares	12,250		12,210		12,118
Earnings per common share:
Basic	$	0.80	$	0.58	$	0.91
Diluted	$	0.80	$	0.58	$	0.91

Income Taxes

Deferred tax assets and liabilities are recognized for the future tax consequences attributable to temporary differences between the financial statement carrying amounts of assets and liabilities and their respective tax bases, and operating losses and tax credit carry-forwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled.

Fair Value Measurement

The financial assets of the company measured at fair value on a recurring basis are cash equivalents and short-term investments. Our short-term investments are generally classified within level 1 or level 2 of the fair value hierarchy because they are valued using quoted market prices, broker or dealer quotations, or alternative pricing sources with reasonable levels of price transparency.

The types of instruments valued based on quoted market prices in active markets include most U.S. government and agency securities and most money market securities. Such instruments are generally classified within level 1 of the fair value hierarchy.

The type of instruments valued based on quoted prices in markets that are not active, broker or dealer quotations, or alternative pricing sources with reasonable levels of price transparency include most investment-grade corporate bonds, and state, municipal and provincial obligations. Such instruments are generally classified within level 2 of the fair value hierarchy.

Segments and Related Information

Management believes that it operates in one business segment. Although our MD&A disclosures describe product lines in which we conduct our business; these product lines are managed and operated as one business segment. ASC 280-10-50, “Operating Segments”, define the characteristics of an operating segment as a) being engaged in business activity from which it may earn revenue and incur expenses, b) being reviewed by the company's chief operating decision maker (CODM) for decisions about resources to be allocated and assess its performance and c) having discrete financial information. Although we indeed look at our product to analyze the nature of our revenue, other financial information, such as certain costs and expenses, net income and EBITDA are not captured or analyzed by these categories. Therefore discrete financial information is not available by product line and our CODM does not make resource allocation decisions or assess the performance of the business based on these categories, but rather in the aggregate.

However, should a portion of our business be considered an operating segment; management has additionally reviewed the criteria for aggregation. ASC 280-10-50-11, “Aggregation Criteria”, allows for the aggregation of operating segments if the segments have similar economic characteristics and if the segments are similar in each of the following areas:


•	The nature of the products and services;


•	The nature of the production processes;


•	The type or class of customer for their products and services;


•	The methods used to distribute their products or provide their services; and


•	The nature of the regulatory environment, if applicable.

The Company is engaged in the business of designing and manufacturing compressors and flares. Our compressors and flares are sold and rented to our customers. In addition, we provide service and maintenance on compressors in our fleet and to third parties.These business activities are similar in all geographic areas. Our manufacturing process is essentially the same for the entire Company and is performed in house at our facilities in Midland, Texas and Tulsa, Oklahoma. Our customers primarily consist of entities in the business of producing natural gas. The maintenance and service of our products is consistent across the entire Company and is performed via an internal fleet of vehicles. The regulatory environment is similar in every jurisdiction in that the most impacting regulations and practices are the result of federal energy policy. In addition, the economic characteristics of each customer arrangement are similar in that we maintain policies at the corporate level..

Therefore, the Company believes that should product lines be considered separate operating segments, they meet the requirements for aggregation as described above.

Recently Issued Accounting Pronouncements

In June 2011, the Financial Accounting Standards Board ("FASB") issued ASU 2011-05, Presentation of Comprehensive Income. Currently, companies have three alternatives for presenting Comprehensive Income and its components in financial statements. Comprehensive income and its components may be reported below the total of net income in a single statement that reports the results of operations, in a separate statement of comprehensive income that begins with net income, or within the statement of changes in equity. Among the changes, ASU 2011-05 eliminates the option for entities to disclose comprehensive income and its components in the statement of changes in equity and as such, requires entities to report comprehensive income and its components either in a single continuous financial statement or in two separate but consecutive statements. In the case in which a single continuous financial statement is utilized, no longer will the statement be titled “Statement of Income and Comprehensive Income” and instead the statement will solely be titled “Statement of Comprehensive Income.” We do not expect the adoption of ASU 2011-05 to have an impact on the presentation of our financial statements.

In September 2011, FASB issued ASU 2011-08, Testing Goodwill for Impairment. Under the amendments in this Update, an entity has the option to first assess qualitative factors to determine whether the existence of events or circumstances leads to a determination that it is more likely than not that the fair value of a reporting unit is less than its carrying amount. If, after assessing the totality of events or circumstances, an entity determines it is not more likely than not that the fair value of a reporting unit is less than its carrying amount, then performing the two-step impairment test is unnecessary. However, if an entity concludes otherwise, then it is required to perform the first step of the two-step impairment test by calculating the fair value of the reporting unit and comparing the fair value with the carrying amount of the reporting unit. If the carrying amount of a reporting unit exceeds its fair value, then the entity is required to perform the second step of the goodwill impairment test to measure the amount of the impairment loss, if any. Under the amendments in this Update, an entity has the option to bypass the qualitative assessment for any reporting unit in any period and proceed directly to performing the first step of the two-step goodwill impairment test. An entity may resume performing the qualitative assessment in any subsequent period. The amendments are effective for annual and interim goodwill impairment tests performed for fiscal years beginning after December 15, 2011. Early adoption is permitted, for year ended December 31, 2011. We have continued to assess goodwill consistent with previous years.

Rental Activity

12 Months Ended

Dec. 31, 2011

Rental Activity [Abstract]

Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]

Rental Activity

We rent natural gas compressor packages to entities in the petroleum industry. These rental arrangements are classified as operating leases and generally have original terms of six months to two years and continue on a month-to-month basis thereafter. Future minimum rent payments for arrangements not on a month-to-month basis at December 31, 2011 are as follows :



Years Ending December 31, (in thousands)
2012	$	7,883
Thereafter	—
Total	$	7,883

Property and Equipment

12 Months Ended

Dec. 31, 2011

Property and Equipment [Abstract]

Property, Plant and Equipment Disclosure [Text Block]

Property and Equipment

Property and equipment consists of the following at December 31, 2011 and 2010 (in thousands):



	Useful Lives (Years)	2011			2010
Land and building	30	$	5,459		$	5,036
Leasehold improvements	39	758			758
Office equipment and furniture	5	1,321			1,229
Software	5	551			550
Machinery and equipment	7	2,337			2,241
Vehicles	3	5,198			5,234
Less accumulated depreciation		(7,785		)	(7,899		)
Total		$	7,839		$	7,149

Depreciation expense for property and equipment and the compressors described in Note 2 was $13.8 million, $11.7 million and $11.4 million for the years ended December 31, 2011, 2010 and 2009, respectively.

- Definition

The entire disclosure for long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale. Examples include land, buildings, machinery and equipment, and other types of furniture and equipment including, but not limited to, office equipment, furniture and fixtures, and computer equipment and software. This disclosure may include property plant and equipment accounting policies and methodology, a schedule of property, plant and equipment gross, additions, deletions, transfers and other changes, depreciation, depletion and amortization expense, net, accumulated depreciation, depletion and amortization expense and useful lives, income statement disclosures, assets held for sale and public utility disclosures.

+ References + Details

Credit Facility	12 Months Ended
Credit Facility	Dec. 31, 2011
Credit Facility [Abstract]
Short-term Debt [Text Block]	Credit Facility Line of Credit Our revolving line of credit agreement with WNB allowed us to borrow, repay and re-borrow funds drawn under this agreement, as amended. The total amount that we could borrow and have outstanding at any one time was the lesser of $40.0 million or the amount available for advances under a “borrowing base” calculation established by the bank. The amount of the borrowing base was based primarily upon our receivables, equipment and inventory. The borrowing base was re-determined by the bank on a monthly basis. Interest only on borrowings under the revolving line of credit agreement was payable monthly on the first day of each month. As of December 31, 2009, we had borrowed $7.0 million under the line of credit. The outstanding principal balance was paid in full on July 1, 2010, and the line expired on that date. Term Loan Facility We previously had a term loan agreement which commenced November 1, 2006. Principal under this term loan agreement was due and payable in 59 monthly installments of $282,000 each. Interest on the unpaid principal balance was due and payable on the same dates as principal payments. As of December 31, 2009, this term loan agreement had a principal balance of $6.2 million. This agreement was paid off in full terminated in December 2010. Senior Bank Borrowings On December 31, 2010, we paid off our existing term loan at Western National Bank ("WNB") and established a $20 million senior secured revolving credit agreement (subject to a right, on an uncommitted basis, to increase the commitments thereunder to up to $40 million) with JP Morgan Chase Bank, N.A. (the "Credit Agreement"). In connection with establishing the Credit Agreement, we paid $2,816,106 to WNB which represented payment in full of the principal and interest owed under our term loan with WNB. In making this payment, we drew $2,000,000 on the line of credit under the Credit Agreement described above. On December 30, 2011, we amended and renewed the Credit Agreement, which was set to expire on December 31, 2011 ("the Amended Credit Agreement"). The Amended Credit Agreement increased our aggregate commitment amount from $20 million to $30 million, subject to collateral availability. We also have a right to request from the lender, on an uncommitted basis, an increase of up to $20 million on the aggregate commitment (which could potentially increase the commitment amount to $50 million). The maturity date was extended to December 31, 2014, and the interest rate terms were amended.\ Borrowing Base. At any time before the maturity of the Amended Credit Agreement, we may draw, repay and re-borrow amounts available under the borrowing base up to the maximum aggregate availability discussed above. Generally, the borrowing base equals the sum of (a) 80% of our eligible accounts receivable plus (b) 50% of the book value of our eligible general inventory (not to exceed 50% of the commitment amount at the time) plus (c) 75% of the book value of our eligible equipment inventory. JPMorgan Chase Bank (the “Lender”) may adjust the borrowing base components if material deviations in the collateral are discovered in future audits of the collateral. Interest and Fees. Under the terms of the Amended Credit Agreement, we have the option of selecting the applicable variable rate for each revolving loan, or portion thereof, of either (a) LIBOR multiplied by the Statutory Reserve Rate (as defined in the Amended Credit Agreement), with respect to this rate, for Eurocurrency funding, plus the Applicable Margin (“LIBOR-based”), or (b) CB Floating Rate, which is the Lender’s Prime Rate less the Applicable Margin; provided, however, that no more than three LIBOR-based borrowings under the agreement may be outstanding at any one time. For purposes of the LIBOR-based interest rate, the Applicable Margin ranges is 1.50%. For purposes of the CB Floating Rate, the Applicable Margin is 1.25%. Accrued interest is payable monthly on outstanding principal amounts, provided that accrued interest on LIBOR-based loans is payable at the end of each interest period, but in no event less frequently than quarterly. In addition, fees and expenses are payable in connection with our requests for letters of credit (generally equal to the Applicable Margin for LIBOR-related borrowings multiplied by the face amount of the requested letter of credit) and administrative and legal costs. Maturity. The maturity date of the Amended Credit Agreement is December 31, 2014, at which time all amounts borrowed under the agreement will be due and outstanding letters of credit must be cash collateralized. The agreement may be terminated early upon our request or the occurrence of an event of default. Security. The obligations under the Amended Credit Agreement are secured by a first priority lien on all of our inventory and accounts and leases receivables, along with a first priority lien on a variable number of our leased compressor equipment the book value of must be maintained at a minimum of 2.00 to 1.00 commitment coverage ration (such ratio being equal to (i) the amount of the borrowing base as of such date to (ii) the amount of the commitment as of such date.) Covenants. The Amended Credit Agreement contains customary representations and warranties, as well as covenants which, among other things, limit our ability to incur additional indebtedness and liens; enter into transactions with affiliates; make acquisitions in excess of certain amounts; pay dividends; redeem or repurchase capital stock or senior notes; make investments or loans; make negative pledges; consolidate, merge or effect asset sales; or change the nature of our business. Events of Default and Acceleration. The Amended Credit Agreement contains customary events of default for credit facilities of this size and type, and includes, without limitation, payment defaults; defaults in performance of covenants or other agreements contained in the transaction documents; inaccuracies in representations and warranties; certain defaults, termination events or similar events; certain defaults with respect to any other Company indebtedness in excess of $50,000; certain bankruptcy or insolvency events; the rendering of certain judgments in excess of $150,000; certain ERISA events; certain change in control events and the defectiveness of any liens under the secured revolving credit agreement. Obligations under the Amended Credit Agreement may be accelerated upon the occurrence of an event of default. As of December 31, 2011 and 2010, we were in compliance with all covenants in our respective loan agreements. A default under our Amended Credit Agreement could trigger the acceleration of our bank debt so that it is immediately due and payable. Such default would have a material adverse effect on our liquidity, financial position and operations.

- Definition

The entire disclosure for information about short-term and long-term debt arrangements, which includes amounts of borrowings under each line of credit, note payable, commercial paper issue, bonds indenture, debenture issue, own-share lending arrangements and any other contractual agreement to repay funds, and about the underlying arrangements, rationale for a classification as long-term, including repayment terms, interest rates, collateral provided, restrictions on use of assets and activities, whether or not in compliance with debt covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with debt covenants.

+ References + Details

Other Long-term Liabilities	12 Months Ended
Other Long-term Liabilities	Dec. 31, 2011
Other Long-term Liabilities [Abstract]
Other Liabilities Disclosure [Text Block]	Other Long-term Liabilities As of December 31, 2011 and 2010, we had a long-term liability of $275,000 to Midland Development Corporation. This amount is to be recognized as income contingent upon certain staffing requirements in the future. In addition, we entered into a purchase agreement with a vendor on July 30, 2008 pursuant to which we agreed to purchase up to $4.8 million of our paint and coating requirements exclusively from the vendor. In connection with the execution of the agreement, the vendor paid us a $300,000 fee which is considered to be a discount toward future purchases from the vendor. The $300,000 payment we received is recorded as a long-term liability and will decrease as the purchase commitment is fulfilled. The long-term liability remaining for the purchase commitment was $248,000 and $253,000 as of December 31, 2011 and 2010, respectively.

Income Taxes

12 Months Ended

Dec. 31, 2011

Income Taxes [Abstract]

Income Tax Disclosure [Text Block]

Income Taxes

The provision for income taxes consists of the following (in thousands):



	2011		2010		2009
Current provision:
Federal	$	—	$	—	$	1,522
State	75		24		234
	75		24		1,756
Deferred provision:
Federal	5,166		4,009		4,179
State	628		239		277
	5,794		4,248		4,456
	$	5,869	$	4,272	$	6,212

The income tax effects of temporary differences that give rise to significant portions of deferred income tax assets and (liabilities) are as follows (in thousands):



	2011			2010
Deferred income tax assets:
Net operating loss carryover	$	6,828		$	2,523
Other	1,218			685
Total deferred income tax assets	$	8,046		$	3,208
Deferred income tax liabilities:
Property and equipment	(43,716		)	(31,811		)
Goodwill and other intangible assets	(1,099		)	(1,143		)
Other	—			—
Total deferred income tax liabilities	(44,815		)	(32,954		)
Net deferred income tax liabilities	$	(36,769	)	$	(29,746	)

The effective tax rate differs from the statutory rate as follows:



	2011		2010		2009
Statutory rate	34	%	34	%	34	%
State and local taxes	3	%	2	%	2	%
Other	1	%	2	%	—	%
Effective rate	38	%	38	%	36	%

Our policy regarding income tax interest and penalties is to expense those items as general and administrative expense. During the years ended December 31, 2011, 2010 and 2009, there were no significant income tax interest or penalty items in the income statement.

We had a regular income tax net operating loss carry forward of $19.3 million for federal income taxes as of December 31, 2011. This net operating loss will begin to expire in 2031. We file income tax returns in the U.S. federal jurisdiction and various state jurisdictions. With few exceptions, we are no longer subject to U.S. federal or state income tax examination by tax authorities for years before 2006.

We are subject to extensive tax laws and regulations, including federal, state and local income taxes and value-based taxes such as excise, sales/use, payroll, franchise and ad valorem taxes. As new tax laws and regulations are enacted and changes are made to existing tax laws and regulations we may be subject to increased future tax expenditures. Our tax positions and the resulting liabilities are subject to audits by the respective taxing authority. These audits may result in additional taxes as well as interest and penalties. We are not aware of any tax positions for which the outcome is uncertain or which is subject to a current review by any tax authority associated with our filings. We have also not established a reserve for any potential obligation related to uncertain tax position.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 08
-Paragraph h
-Article 4

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 109
-Paragraph 136, 172
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 109
-Paragraph 43, 44, 45, 46, 47, 48, 49
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32718-109319

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32639-109319

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(h))
-URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e23780-122690

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32537-109319

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32559-109319

+ Details

Stockholders' Equity	12 Months Ended
Stockholders' Equity	Dec. 31, 2011
Stockholders' Equity Attributable to Parent [Abstract]
Stockholders' Equity Note Disclosure [Text Block]	Stockholders' Equity Preferred Stock We have a total of 5.0 million authorized preferred shares with rights and preferences as designated by the Board of Directors. As of December 31, 2011 and 2010, there were no issued or outstanding preferred shares. Securities offering On August 14, 2009 we filed a universal shelf registration statement on Form S-3 with the Securities and Exchange Commission ("SEC") to register up to $150,000,000 of securities, including debt securities, common stock, preferred stock, depository shares, rights to purchase common stock and warrants to purchase any of the foregoing securities. The SEC has declared the statement effective, and we may issue any of the registered securities from time to time in one or more offerings depending on market conditions and our financing needs. Restricted Securities On June 16, 2009, at our annual meeting of shareholders, our shareholders adopted the 2009 Restricted Stock/Unit Plan. A total of 300,000 shares of Company common stock are reserved for issuance under the restricted stock plan. During January 2011, we awarded 49,110 restricted shares of stock under the 2009 Restricted Stock Plan for payment of the executive bonus plan of 2009. Of these restricted shares, 20,000 vest over a one-year period and the remainder vest over a three-year period, beginning on the date of grant. Compensation expense related to the restricted shares was approximately $607,000, for the year ended December 31, 2011. As of December 31, 2011, there was a total of approximately $224,000 of unrecognized compensation expense related to the nonvested portion of these restricted shares. This expense is expected to be recognized over the next two years.

- Definition

The entire disclosure for shareholders' equity, comprised of portions attributable to the parent entity and noncontrolling interest, if any, including other comprehensive income (as applicable). Including, but not limited to: (1) balances of common stock, preferred stock, additional paid-in capital, other capital and retained earnings; (2) accumulated balance for each classification of other comprehensive income and total amount of comprehensive income; (3) amount and nature of changes in separate accounts, including the number of shares authorized and outstanding, number of shares issued upon exercise and conversion, and for other comprehensive income, the adjustments for reclassifications to net income; (4) rights and privileges of each class of stock authorized; (5) basis of treasury stock, if other than cost, and amounts paid and accounting treatment for treasury stock purchased significantly in excess of market; (6) dividends paid or payable per share and in the aggregate for each class of stock for each period presented; (7) dividend restrictions and accumulated preferred dividends in arrears (in aggregate and per share amount); (8) retained earnings appropriations or restrictions, such as dividend restrictions; (9) impact of change in accounting principle, initial adoption of new accounting principle and correction of an error in previously issued financial statements; (10) shares held in trust for Employee Stock Ownership Plan (ESOP); (11) deferred compensation related to issuance of capital stock; (12) note received for issuance of stock; (13) unamortized discount on shares; (14) description, terms, and number of warrants or rights outstanding; (15) shares under subscription and subscription receivables, effective date of new retained earnings after quasi-reorganization and deficit eliminated by quasi-reorganization and, for a period of at least ten years after the effective date, the point in time from which the new retained dates; and (16) retroactive effective of subsequent change in capital structure.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 12
-Paragraph 10
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Article 3

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 4
-Section 08
-Paragraph d

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Research Bulletin (ARB)
-Number 43
-Chapter 1
-Section B
-Paragraph 7, 11A
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 129
-Paragraph 2, 3, 4, 5, 6, 7, 8
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 08
-Article 4

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 5
-Paragraph 15
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 29, 30, 31
-Article 5

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 4
-Section E

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 4
-Section C

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=6959260&loc=d3e187085-122770

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21484-112644

Reference 15: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21564-112644

Reference 16: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21488-112644

Reference 17: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(d),(e))
-URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e23780-122690

Reference 18: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21506-112644

Reference 19: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 30
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6405834&loc=d3e23285-112656

Reference 20: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB TOPIC 4.E)
-URI http://asc.fasb.org/extlink&oid=6228006&loc=d3e74512-122707

Reference 21: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Preferred Stock
-URI http://asc.fasb.org/extlink&oid=6521494

Reference 22: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.29-31)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 23: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SAB TOPIC 4.C)
-URI http://asc.fasb.org/extlink&oid=6959260&loc=d3e187143-122770

+ Details

Stock Based Compensation

12 Months Ended

Dec. 31, 2011

Stock-Based Compensation [Abstract]

Disclosure of Compensation Related Costs, Share-based Payments [Text Block]

Stock-Based Compensation

Stock Option Plan

Our 1998 Stock Option Plan (the "Plan"), which is stockholder approved, permits the grant of stock options to its employees for up to 550,000 shares of common stock. On June 16, 2009, at our annual meeting of shareholders, our shareholders approved a proposed amendment to the Plan to add additional 200,000 shares of common stock to the Plan, thereby authorizing the issuance of up to 750,000 shares of common stock under the Plan. We believe that such awards better align the interests of our employees with our stockholders. Option awards are generally granted with an exercise price equal to the market price of our stock at the date of grant; those option awards generally vest based on three years of continuous service and have ten-year contractual terms. Certain option and share awards provide for accelerated vesting if there is a change in control of the Company (as defined in the Plan). The last date that grants can be made under the Plan is March 1, 2016. As of December 31, 2011, 293,357 shares were still available for issue under the Plan.

The fair value of each option award is estimated on the date of grant using the Black-Scholes option valuation model that uses the assumptions noted in the following table. The risk-free rate for periods within the contractual life of the option is based on the U.S. Treasury yield curve in effect at the time of grant. The expected life of options granted is based on the vesting period and historical exercise and post-vesting employment termination behavior for similar grants. We use historical data to estimate option exercise and employee termination within the valuation model; separate groups of employees that have similar historical exercise behavior are considered separately for valuation purposes.



Weighted average Black –Scholes fair value assumption	2011		2010		2009
Risk free rate	2.09	%	1.22	%	1.82	%
Expected life	5 yrs		2 yrs		5 yrs
Expected volatility	64.89	%	64.32	%	66.75	%
Expected dividend yield	—		—		—

A summary of all option activity as of December 31, 2011 and changes during the year then ended is presented below.



	Number of Stock Options		Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (years)	Aggregate Intrinsic Value
						(in thousands)
Outstanding at December 31, 2010	423,206		$	14.76	7.33	$	1,858
Granted	30,000		$	17.60
Exercised	(18,571	)	$	10.66		127
Forfeited or expired	(12,396	)	$	17.68		419
Outstanding at December 31, 2011	422,239		$	15.06	6.48	$	766
Exercisable at December 31, 2011	343,573		$	14.56	6.06	$	721

We granted an option to purchase 10,000 shares to our Vice President of Technical Services and 17,000 shares to our non-executive employees on January 24, 2011 at an exercise price of $17.81 with a three year vesting period. We also granted additional options to purchase 3,000 shares to non-executive employees on June 14, 2011 at an exercise price of $15.70 with a three year vesting period.

The weighted average grant date fair value of options granted during the years 2011, 2010 and 2009 was $10.00, $7.30 and $6.68 respectively. The total intrinsic value, or the difference between the exercise price and the market price on the date of exercise, of options exercised during the years ended December 31, 2011, 2010 and 2009 was approximately $127,000, $400,000 and $65,000 respectively. Cash received from stock options exercised during the years ended December 31, 2011, 2010 and 2009 was $123,000, $407,000 and $49,000, respectively.

The following table summarizes information about the options outstanding at December 31, 2011:



	Options Outstanding				Options Exercisable
Range of Exercise Prices	Shares	Weighted Average Remaining Contractual Life (years)	Weighted Average Exercise Price		Shares	Weighted Average Exercise Price
0.00 – 5.58	7,500	1.67	$	4.99	7,500	$	4.99
5.59 – 9.43	94,239	4.98	8.63		94,239	8.63
9.44 – 15.60	65,000	5.99	12.34		55,000	12.77
15.61 – 20.48	255,500	7.29	18.42		186,834	18.46
0.00 - 20.48	422,239	6.48	$	15.06	343,573	$	14.56

The summary of the status of our unvested stock options as of December 31, 2011 and changes during the year then ended is presented below:



	Unvested Stock Options		Weighted Average Grant Date Fair Value
Unvested at December 31, 2010	116,333		$	8.18
Granted	30,000		10.01
Vested	(67,667	)	8.25
Forfeited	—		—
Unvested at December 31, 2011	78,666		$	8.82

We recognized stock compensation expense from stock options vesting of $461,000, $804,000 and $584,000, respectively, for the years ended December 31, 2011, 2010 and 2009. The total income tax benefit recognized in the income statement for stock based compensation was $148,000, $137,000 and $23,000, respectively, for the years ended December 31, 2011, 2010 and 2009. As of December 31, 2011, there was approximately $411,000 of total unamortized compensation cost related to unvested stock options. We expect to recognize such cost over a weighted-average period of 1.5 years. There was no income tax benefit realized for the tax deductions from stock options exercised for the years ending 2011, 2010 and 2009.

- Definition

The entire disclosure for compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph 64, 65, A240
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Statement of Position (SOP)
-Number 93-6
-Paragraph 53
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 14

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 50
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6406099&loc=d3e25284-112666

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5047-113901

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5444-113901

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 40
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6418621&loc=d3e17540-113929

+ Details

Commitments and Contingencies

12 Months Ended

Dec. 31, 2011

Commitments [Abstract]

Commitments Disclosure [Text Block]

Commitments and Contingencies

401(k) Plan

We offer a 401(k) Plan to all employees that have reached the age of eighteen and have completed six months of service. The participants may contribute up to 100% of their salary subject to IRS limitations. Employer contributions are subject to Board discretion and are subject to a vesting schedule of 20% each year after the first year and 100% after six years. We contributed $410,000, $185,000, and $211,000 to the 401(k) Plan in 2011, 2010 and 2009, respectively.

Rented Facilities

We lease certain of our facilities under operating leases with terms generally ranging from month-to-month to five years. Most facility leases contain renewal options. Remaining future minimum rental payments due under these leases for the years ended December 31 are as follows (in thousands):



2012	$	244
2013	167
2014	17
2015	—
Total	$	428

Rent expense under such leases was $450,000, $526,000, and $466,000 for the years ended December 31, 2011, 2010 and 2009, respectively.

Legal Proceedings

From time to time, we are a party to various legal proceedings in the ordinary course of our business. While management is unable to predict the ultimate outcome of these actions, it believes that any ultimate liability arising from these actions will not have a material effect on our financial position, results of operations or cash flow. We are not currently a party to any bankruptcy, receivership, reorganization, adjustment or similar proceeding, and we are not aware of any other threatened litigation.

- Definition

The entire disclosure for commitments and contingencies.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name FASB Interpretation (FIN)
-Number 14
-Paragraph 3
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 5
-Paragraph 9, 10, 11, 12
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.25)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=6952336&loc=d3e14435-108349

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6398077&loc=d3e12565-110249

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 440
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6394976&loc=d3e25287-109308

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6449706&loc=d3e16207-108621

+ Details

Segment Information

12 Months Ended

Dec. 31, 2011

Segment Information [Abstract]

Segment Reporting Disclosure [Text Block]

Segment Information

Our management identifies segments based upon major revenue sources as shown in the tables below. However, management does not track assets by segment. All sales and assets are currently located in continental United Sates.

For the Year Ended December 31, 2011



	Sales		Rental		Service & Maintenance		Corporate			Total
	(in thousands of dollars)
Revenue	$	15,419	$	48,619	$	1,120	$	—		$	65,158
Operating costs and expenses	9,194		20,742		458		19,904			50,298
Other income/(expense)	—		—		—		769			769
Income (loss) before provision for income taxes	$	6,225	$	27,877	$	662	$	(19,135	)	$	15,629

For the Year Ended December 31, 2010



	Sales		Rental		Service & Maintenance		Corporate			Total
	(in thousands of dollars)
Revenue	$	12,370	$	40,670	$	868	$	—		$	53,908
Operating costs and expenses	8,010		16,205		535		17,794			42,544
Other income/(expense)	—		—		—		(64		)	(64		)
Income (loss) before provision for income taxes	$	4,360	$	24,465	$	333	$	(17,858	)	$	11,300

For the Year Ended December 31, 2009



	Sales		Rental		Service & Maintenance		Corporate			Total
	(in thousands of dollars)
Revenue	$	21,657	$	45,146	$	993	$	—		$	67,796
Operating costs and expenses	14,880		16,600		677		17,876			50,033
Other income/(expense)	—		—		—		(536		)	(536		)
Income (loss) before provision for income taxes	$	6,777	$	28,546	$	316	$	(18,412	)	$	17,227

- Definition

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 131
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 34
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8981-108599

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 35
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8984-108599

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 42
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e9054-108599

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 40
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e9031-108599

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 31
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8924-108599

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8538-108599

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8906-108599

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 41
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e9038-108599

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 29
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8864-108599

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8971-108599

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 26
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8844-108599

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8380-108599

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8595-108599

Reference 15: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8933-108599

+ Details

Quarterly Financial Data

12 Months Ended

Dec. 31, 2011

Quarterly Financial Data – Unaudited [Abstract]

Quarterly Financial Information [Text Block]

Quarterly Financial Data (in thousands, except per share data) – Unaudited



2011	Q1		Q2		Q3		Q4		Total
Total revenue	$	15,054	$	13,758	$	17,701	$	18,645	$	65,158
Operating income	3,329		3,222		3,643		4,666		14,860
Net income applicable to common shares	2,497		2,008		2,231		3,024		9,760
Net income per share - Basic	0.21		0.16		0.18		0.25		0.80
Net income per share - Diluted	0.20		0.16		0.18		0.25		0.80



2010	Q1		Q2		Q3		Q4		Total
Total revenue	$	11,549	$	11,901	$	14,245	$	16,213	$	53,908
Operating income	2,228		2,394		3,363		3,379		11,364
Net income applicable to common shares	1,364		1,544		2,153		1,967		7,028
Net income per share - Basic	0.11		0.13		0.18		0.16		0.58
Net income per share - Diluted	0.11		0.13		0.18		0.16		0.58

- Definition

The entire disclosure for the quarterly financial data in the annual financial statements. The disclosure may include a tabular presentation of financial information for each fiscal quarter for the current and previous year, including revenues, gross profit, income or loss before extraordinary items and earnings per share data. It also includes an indication if the information in the note is unaudited, comments on the aggregate effect of year-end adjustments, and an explanation of matters or transactions that affect comparability or are pertinent to an understanding of the information furnished.

+ References + Details

Subsequent Events	12 Months Ended
Subsequent Events	Dec. 31, 2011
Subsequent Events [Abstract]
Subsequent Events [Text Block]	Subsequent Events On March 12, 2012, the Company entered into an agreement to sell forty eight compressors from our rental fleet to an existing customer. Under the terms of the agreement, the units will be conveyed on the later of the scheduled delivery dates or receipt of payment. There are two scheduled delivery dates, the first delivery for twenty four units is scheduled for March 15, 2012 and the second delivery of twenty four units is scheduled for April 1, 2012. The total sale of the used units is $10.7 million. Prior to this sale, the remaining contract period for these units sold varied from two to eleven months with total expected rental income of $964,000.