CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Cash and cash equivalents	$ 231,129	$ 374,289
Accounts receivable	1,372,054	1,415,063
Retainage receivable	683,966	648,441
Costs and estimated earnings in excess of billings	1,346,974	1,236,734
Other current assets	252,735	249,455
Accumulated depreciation	475,207	434,294
Property and equipment, net	456,693	489,217
Unamortized discount and debt issuance costs, current	0	2,040
Accounts payable	692,835	794,611
Retainage payable	331,341	315,135
Billings in excess of costs and estimated earnings	764,029	839,222
Accrued expenses and other current liabilities	200,138	215,207
Unamortized discount and debt issuance costs, non-current	$ 18,712	$ 20,209
Preferred stock, shares authorized (in shares)	1,000,000	1,000,000
Preferred stock, par value (in dollars per share)	$ 1	$ 1
Preferred stock, shares issued (in shares)	0	0
Common stock, shares authorized (in shares)	112,500,000	112,500,000
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shares issued (in shares)	51,072,182	50,827,205
Common stock, shares outstanding (in shares)	51,072,182	50,827,205
VIEs
Cash and cash equivalents	$ 91,700	$ 105,735
Accounts receivable	85,873	86,012
Retainage receivable	139,617	122,335
Costs and estimated earnings in excess of billings	90,294	39,846
Other current assets	49,867	51,746
Property and equipment, net	4,550	12,840
Accounts payable	86,263	116,461
Retainage payable	30,681	26,439
Billings in excess of costs and estimated earnings	344,239	362,427
Accrued expenses and other current liabilities	$ 7,096	$ 9,595