CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash flows from operating activities:
Net income	$ 34,262	$ 18,298	$ 16,122
Adjustments to reconcile net income to net cash flows provided by operating activities-
Depreciation and amortization of property and equipment	24,821	19,176	15,955
Amortization of intangible assets	335	335	335
Stock-based compensation expense	2,923	2,130	1,603
Deferred income taxes	2,687	(1,326)	1,743
Gain on sale of property and equipment	(1,019)	(1,174)	(750)
Other non-cash items	110	44	85
Changes in operating assets and liabilities
Accounts receivable, net	(40,330)	(19,739)	(6,520)
Costs and estimated earnings in excess of billings on uncompleted contracts	(18,079)	(14,395)	1,441
Construction materials inventory	4,003	(4,003)
Receivable for insurance claims in excess of deductibles	(1,257)	(1,700)	(340)
Other assets	(1,619)	2,293	464
Accounts payable	11,067	35,062	(1,718)
Billings in excess of costs and estimated earnings on uncompleted contracts	7,644	(20,560)	19,842
Accrued self insurance	733	4,806	944
Other liabilities	3,718	11,147	(4,369)
Net cash flows provided by operating activities	29,999	30,394	44,837
Cash flows from investing activities:
Proceeds from sale of property and equipment	1,204	1,306	1,278
Purchases of property and equipment	(37,249)	(42,342)	(21,895)
Net cash flows used in investing activities	(36,045)	(41,036)	(20,617)
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	1,309	1,290	671
Excess tax benefit from stock-based awards	524	1,266	198
Debt issuance costs	(13)	(569)
Payments of capital lease obligations			(42)
Other financing activities	38	45
Net cash flows provided by (used in) financing activities	(8,142)	(17,968)	827
Net increase (decrease) in cash and cash equivalents	(14,188)	(28,610)	25,047
Cash and cash equivalents:
Beginning of period	34,013	62,623	37,576
End of period	$ 19,825	$ 34,013	$ 62,623