CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Cash and cash equivalents	$ 221,878	$ 146,103
Accounts receivable	1,857,870	1,743,300
Accounts receivable, retainage	574,710	569,391
Accumulated depreciation	345,546	313,783
Accounts payable	949,675	994,016
Accounts payable, retainage	267,110	258,294
Billings in excess of costs and estimated earnings	403,635	331,112
Unamortized discount and debt issuance cost	$ 54,699	$ 56,072
Preferred stock, shares authorized	1,000,000	1,000,000
Preferred stock, par value (in dollars per share)	$ 1	$ 1
Preferred stock, shares issued	0	0
Common stock, shares authorized	75,000,000	75,000,000
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shares issued	49,781,010	49,211,353
Common stock, shares outstanding	49,781,010	49,211,353
Variable Interest Entity, Primary Beneficiary [Member]
Cash and cash equivalents	$ 79,111	$ 0
Accounts receivable	36,317	0
Accounts payable	4,826	0
Billings in excess of costs and estimated earnings	$ 91,750	$ 0