CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Cash and cash equivalents	$ 138,569	$ 192,868
Accounts receivable	1,272,932	1,265,717
Retainage receivable	490,751	535,939
Other current assets	141,472	89,316
Accumulated depreciation	337,101	359,188
PROPERTY AND EQUIPMENT, net of accumulated depreciation	490,614	467,499
Accounts payable	625,436	699,971
Billings in excess of costs and estimated earnings	574,392	456,869
Unamortized discounts and debt issuance costs	$ 40,437	$ 45,631
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	50,010,863	49,781,010
Common stock, shares outstanding	50,010,863	49,781,010
Variable Interest Entity, Primary Beneficiary [Member]
Cash and cash equivalents	$ 53,575	$ 53,067
Accounts receivable	57,008	30,003
Retainage receivable	24,288	12,410
Other current assets	35,657	0
PROPERTY AND EQUIPMENT, net of accumulated depreciation	41,150	11,641
Accounts payable	44,118	19,243
Billings in excess of costs and estimated earnings	$ 240,545	$ 120,952