CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Cash and cash equivalents	$ 207,130	$ 116,075
Accounts receivable	1,460,450	1,261,072
Retainage receivable	542,274	478,744
Other current assets	162,406	115,527
Accumulated depreciation	375,717	343,735
PROPERTY AND EQUIPMENT, net of accumulated depreciation	509,986	490,669
Accounts payable	670,458	621,728
Retainage payable	232,209	211,956
Accrued expenses and other current liabilities	188,373	174,325
Billings in excess of costs and estimated earnings	818,806	573,190
Unamortized discounts and debt issuance costs	$ 26,358	$ 34,998
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	50,278,816	50,025,996
Common stock, shares outstanding	50,278,816	50,025,996
Variable Interest Entity, Primary Beneficiary [Member]
Cash and cash equivalents	$ 110,447	$ 43,131
Accounts receivable	142,749	62,482
Retainage receivable	73,424	36,724
Other current assets	36,859	30,185
PROPERTY AND EQUIPMENT, net of accumulated depreciation	54,729	51,508
Accounts payable	74,183	18,070
Retainage payable	10,294	0
Accrued expenses and other current liabilities	37,935	34,828
Billings in excess of costs and estimated earnings	$ 404,357	$ 263,764