CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Cash and cash equivalents	$ 118,258	$ 192,868
Accounts receivable	1,325,465	1,265,717
Retainage receivable	492,937	535,939
Other current assets	130,023	89,316
Accumulated depreciation	345,405	359,188
PROPERTY AND EQUIPMENT, net of accumulated depreciation	494,498	467,499
Accounts payable	611,100	699,971
Accrued expenses and other current liabilities	162,102	132,438
Billings in excess of costs and estimated earnings	648,287	456,869
Unamortized discounts and debt issuance costs	$ 37,749	$ 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	50,025,996	49,781,010
Common stock, shares outstanding	50,025,996	49,781,010
Variable Interest Entity, Primary Beneficiary [Member]
Cash and cash equivalents	$ 32,040	$ 53,067
Accounts receivable	75,999	30,003
Retainage receivable	31,694	12,410
Other current assets	33,033	0
PROPERTY AND EQUIPMENT, net of accumulated depreciation	47,559	11,641
Accounts payable	10,793	19,243
Accrued expenses and other current liabilities	46,164	0
Billings in excess of costs and estimated earnings	$ 261,187	$ 120,952