CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Cash flows from operating activities:
Net income	$ 8,512	$ 2,916
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation	14,134	15,281
Amortization of intangible assets	1,727	1,624
Stock-based compensation expense	459	262
Gain on sale of property and equipment	(1,308)	(736)
Changes in assets and liabilities:
Customer retention deposits	104	(241)
Accounts receivable	18,225	(20,513)
Costs and estimated earnings in excess of billings	9,004	(24,155)
Other current assets	5,525	(3,265)
Other long-term assets	(147)	(395)
Accounts payable	(43,997)	11,978
Billings in excess of costs and estimated earnings	38,165	(14,217)
Accrued expenses and other current liabilities	(1,392)	(3,469)
Other long-term liabilities	77	(678)
Net cash provided by (used in) operating activities	49,088	(35,608)
Cash flows from investing activities:
Purchase of property and equipment	(19,222)	(12,255)
Proceeds from sale of property and equipment	1,984	3,306
Cash paid for acquisitions		(4,108)
Net cash used in investing activities	(17,238)	(13,057)
Cash flows from financing activities:
Repayment of capital leases	(82)	(268)
Repayment of long-term debt	(12,416)	(11,977)
Proceeds from issuance of common stock purchased by management under long-term incentive plan	1,148	1,439
Repurchase of common stock	(4,999)
Dividends paid	(2,839)	(2,842)
Net cash used in financing activities	(19,188)	(13,648)
Net change in cash and cash equivalents	12,662	(62,313)
Cash and cash equivalents at beginning of the period	135,823	161,122
Cash and cash equivalents at end of the period	148,485	98,809
Cash paid:
Interest	2,262	2,172
Income taxes, net of refunds received	1,872	995
SUPPLEMENTAL DISCLOSURES OF NONCASH INVESTING AND FINANCING ACTIVITIES
Obligations incurred for the acquisition of property	4,163
Dividends declared and not yet paid	$ 2,829	$ 2,847