CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash flows from operating activities:
Net income	$ 34,759	$ 34,262	$ 18,298
Adjustments to reconcile net income to net cash flows provided by operating activities -
Depreciation and amortization of property and equipment	28,860	24,821	19,176
Amortization of intangible assets	335	335	335
Stock-based compensation expense	3,519	2,923	2,130
Deferred income taxes	381	2,687	(1,326)
Gain on sale of property and equipment	(893)	(1,019)	(1,174)
Other non-cash items	151	110	44
Changes in operating assets and liabilities
Accounts receivable, net	(6,227)	(40,330)	(19,739)
Costs and estimated earnings in excess of billings on uncompleted contracts	21,254	(18,079)	(14,395)
Construction materials inventory		4,003	(4,003)
Receivable for insurance claims in excess of deductibles	(10)	(1,257)	(1,700)
Other assets	(2,138)	(1,619)	2,293
Accounts payable	(5,289)	11,067	35,062
Billings in excess of costs and estimated earnings on uncompleted contracts	20,363	7,644	(20,560)
Accrued self insurance	(472)	733	4,806
Other liabilities	469	3,718	11,147
Net cash flows provided by operating activities	95,062	29,999	30,394
Cash flows from investing activities:
Proceeds from sale of property and equipment	1,151	1,204	1,306
Purchases of property and equipment	(42,725)	(37,249)	(42,342)
Net cash flows used in investing activities	(41,574)	(36,045)	(41,036)
Cash flows from financing activities:
Repayments on term loan			(30,000)
Net borrowings (repayments) on revolving credit facility		(10,000)	10,000
Employee stock option transactions	1,762	1,309	1,290
Excess tax benefit from stock-based awards	1,323	524	1,266
Debt issuance costs		(13)	(569)
Other financing activities	56	38	45
Net cash flows provided by (used in) financing activities	3,141	(8,142)	(17,968)
Net increase (decrease) in cash and cash equivalents	56,629	(14,188)	(28,610)
Cash and cash equivalents:
Beginning of period	19,825	34,013	62,623
End of period	$ 76,454	$ 19,825	$ 34,013

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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.