CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Cash flows from operating activities:
Net income	$ 7,172	$ 6,272
Adjustments to reconcile net income to net cash flows provided by (used in) operating activities —
Depreciation and amortization of property and equipment	8,881	7,950
Amortization of intangible assets	83	84
Stock-based compensation expense	1,049	833
Deferred income taxes	(30)	0
Gain on sale of property and equipment	(898)	(11)
Other non-cash items	62	35
Changes in operating assets and liabilities
Accounts receivable, net	1,389	124
Costs and estimated earnings in excess of billings on uncompleted contracts	(20,081)	(7,118)
Receivable for insurance claims in excess of deductibles	50	(695)
Other assets	2,158	1,076
Accounts payable	5,189	(14,195)
Billings in excess of costs and estimated earnings on uncompleted contracts	(5,082)	(4,200)
Accrued self insurance	(951)	623
Other liabilities	2,379	255
Net cash flows provided by (used in) operating activities	1,370	(8,967)
Cash flows from investing activities:
Proceeds from sale of property and equipment	938	42
Purchases of property and equipment	(16,362)	(12,441)
Net cash flows used in investing activities	(15,424)	(12,399)
Cash flows from financing activities:
Proceeds from exercise of stock options	378	0
Excess tax benefit from stock-based awards	1,010	111
Repurchase of common shares	(3,140)	(824)
Net cash flows used in financing activities	(1,752)	(713)
Net decrease in cash and cash equivalents	(15,806)	(22,079)
Cash and cash equivalents:
Beginning of period	77,636	76,454
End of period	$ 61,830	$ 54,375