CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities:
Net income	$ 8,315	$ 8,746	$ 24,737	$ 24,491
Adjustments to reconcile net income to net cash flows provided by operating activities -
Depreciation and amortization of property and equipment	7,258	6,420	21,203	18,167
Amortization of intangible assets	84	84	251	251
Stock-based compensation expense	893	688	2,551	2,029
Deferred income taxes	400	197	400	197
Gain on sale of property and equipment	(256)	(387)	(770)	(707)
Other non-cash items	39	35	114	103
Changes in operating assets and liabilities
Accounts receivable, net	(3,448)	(10,269)	(13,907)	(37,529)
Costs and estimated earnings in excess of billings uncompleted contracts	(5,073)	(8,941)	19,864	(19,413)
Construction materials inventory				4,003
Receivable for insurance claims in excess of deductibles	(192)	(1,401)	(90)	(1,160)
Other assets	(286)	1,135	795	2,379
Accounts payable	2,036	7,176	(18,745)	18,897
Billings in excess of costs and estimated earnings on uncompleted contracts	18,030	1,202	34,429	5,120
Accrued self insurance	(478)	1,291	(390)	779
Other liabilities	6,201	6,617	1,051	5,133
Net cash flows provided by operating activities	33,523	12,593	71,493	22,740
Cash flows from investing activities:
Proceeds from sale of property and equipment	368	513	914	877
Purchases of property and equipment	(9,622)	(11,665)	(31,540)	(32,094)
Net cash flows used in investing activities	(9,254)	(11,152)	(30,626)	(31,217)
Cash flows from financing activities:
Net repayments on revolving credit facility		(10,000)		(10,000)
Employee stock option and restricted stock transactions	653	719	1,175	864
Excess tax benefit from stock-based awards	343	139	971	174
Debt issuance costs				(13)
Other financing activities			56	38
Net cash flows provided by (used in) financing activities	996	(9,142)	2,202	(8,937)
Net increase (decrease) in cash and cash equivalents	25,265	(7,701)	43,069	(17,414)
Cash and cash equivalents:
Beginning of period	37,629	24,300	19,825	34,013
End of period	$ 62,894	$ 16,599	$ 62,894	$ 16,599