CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Contract revenues	$ 244,148us-gaap_SalesRevenueServicesNet	$ 215,638us-gaap_SalesRevenueServicesNet
Contract costs	214,774us-gaap_CostOfServices	188,558us-gaap_CostOfServices
Gross profit	29,374us-gaap_GrossProfit	27,080us-gaap_GrossProfit
Selling, general and administrative expenses	18,592	16,875
Amortization of intangible assets	83us-gaap_AmortizationOfIntangibleAssets	84us-gaap_AmortizationOfIntangibleAssets
Gain on sale of property and equipment	(898)	(11)
Income from operations	11,597us-gaap_OperatingIncomeLoss	10,132us-gaap_OperatingIncomeLoss
Other income (expense)
Interest income	7us-gaap_InvestmentIncomeInterest	3us-gaap_InvestmentIncomeInterest
Interest expense	(179)us-gaap_InterestExpense	(178)us-gaap_InterestExpense
Other, net	(58)us-gaap_OtherNonoperatingIncomeExpense	54us-gaap_OtherNonoperatingIncomeExpense
Income before provision for income taxes	11,367	10,011
Income tax expense	4,195us-gaap_IncomeTaxExpenseBenefit	3,739us-gaap_IncomeTaxExpenseBenefit
Net income	$ 7,172us-gaap_NetIncomeLoss	$ 6,272us-gaap_NetIncomeLoss
Income per common share:
— Basic (in dollars per share)	$ 0.35us-gaap_EarningsPerShareBasic	$ 0.3us-gaap_EarningsPerShareBasic
— Diluted (in dollars per share)	$ 0.34us-gaap_EarningsPerShareDiluted	$ 0.29us-gaap_EarningsPerShareDiluted
Weighted average number of common shares and potential common shares outstanding:
— Basic (in shares)	20,562	21,036
— Diluted (in shares)	21,052	21,513

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6388964&loc=d3e16225-109274

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (a)(2)

-URI http://asc.fasb.org/extlink&oid=26713463&loc=d3e16323-109275