CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Cash flows from operating activities:
Net income	$ 7,575	$ 13,633
Adjustments to reconcile net income to net cash flows provided by (used in) operating activities:
Depreciation and amortization of property and equipment	28,906	28,747
Amortization of intangible assets	593	691
Stock-based compensation expense	3,479	3,488
Deferred income taxes	(302)	(116)
Gain on sale of property and equipment	(2,602)	(1,079)
Other non-cash items	1,113	(38)
Changes in operating assets and liabilities
Accounts receivable, net	(37,059)	1,770
Costs and estimated earnings in excess of billings on uncompleted contracts	(36,980)	(28,774)
Receivable for insurance claims in excess of deductibles	(292)	(1,640)
Other assets	85	7,008
Accounts payable	14,803	11,022
Billings in excess of costs and estimated earnings on uncompleted contracts	1,363	5,454
Accrued self insurance	2,626	299
Other liabilities	(5,098)	32
Net cash flows provided by (used in) operating activities	(21,790)	40,497
Cash flows from investing activities:
Proceeds from sale of property and equipment	2,802	2,544
Purchases of property and equipment	(24,909)	(17,948)
Net cash flows used in investing activities	(22,107)	(15,404)
Cash flows from financing activities:
Net borrowings under revolving lines of credit	20,427	33,407
Payment of principal obligations under capital leases	(812)	(442)
Proceeds from exercise of stock options	1,147	2,080
Repurchase of common shares	(3,058)	(101,483)
Other financing activities	3,718	2,077
Net cash flows provided by (used in) financing activities	21,422	(64,361)
Effect of exchange rate changes on cash	311	55
Net decrease in cash and cash equivalents	(22,164)	(39,213)
Cash and cash equivalents:
Beginning of period	23,846	39,797
End of period	1,682	584
Noncash investing activities:
Acquisition of property and equipment acquired under capital lease arrangements	0	5,580
Noncash financing activities:
Capital lease obligations initiated	$ 0	$ 5,580