CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Cash flows from operating activities:
Net income	$ 14,013	$ 16,422
Adjustments to reconcile net income to net cash flows provided by operating activities -
Depreciation and amortization of property and equipment	16,103	13,945
Amortization of intangible assets	167	167
Stock-based compensation expense	2,197	1,658
Deferred income taxes	(41)
Gain on sale of property and equipment	(71)	(514)
Other non-cash items	47	75
Changes in operating assets and liabilities
Accounts receivable, net	(3,554)	(10,459)
Costs and estimated earnings in excess of billings on uncompleted contracts	(15,717)	24,937
Receivable for insurance claims in excess of deductibles	(1,350)	102
Other assets	206	1,081
Accounts payable	(6,991)	(20,781)
Billings in excess of costs and estimated earnings on uncompleted contracts	448	16,399
Accrued self insurance	1,158	88
Other liabilities	(2,318)	(5,150)
Net cash flows provided by operating activities	4,297	37,970
Cash flows from investing activities:
Proceeds from sale of property and equipment	182	546
Purchases of property and equipment	(25,234)	(21,918)
Net cash flows used in investing activities	(25,052)	(21,372)
Cash flows from financing activities:
Proceeds from exercise of stock options	135	1,045
Excess tax benefit from stock-based awards	230	628
Repurchase of common shares	(1,550)	(523)
Other financing activities	38	56
Net cash flows provided by (used in) financing activities	(1,147)	1,206
Net increase (decrease) in cash and cash equivalents	(21,902)	17,804
Cash and cash equivalents:
Beginning of period	76,454	19,825
End of period	$ 54,552	$ 37,629