CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Cash and cash equivalents	$ 187,535	$ 374,289
Accounts receivable	1,426,709	1,415,063
Retainage receivable	637,124	648,441
Costs and estimated earnings in excess of billings	1,388,010	1,236,734
Other current assets	204,555	249,455
Accumulated depreciation	477,556	434,294
Property and equipment, net	440,982	489,217
Unamortized discount and debt issuance costs, current	0	2,040
Accounts payable	656,135	794,611
Retainage payable	286,036	315,135
Billings in excess of costs and estimated earnings	754,939	839,222
Accrued expenses and other current liabilities	207,850	215,207
Unamortized discount and debt issuance costs, non-current	$ 17,921	$ 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)	51,072,432	50,827,205
Common stock, shares outstanding (in shares)	51,072,432	50,827,205
VIEs
Cash and cash equivalents	$ 72,473	$ 105,735
Accounts receivable	99,841	86,012
Retainage receivable	150,301	122,335
Costs and estimated earnings in excess of billings	142,587	39,846
Other current assets	44,851	51,746
Property and equipment, net	2,413	12,840
Accounts payable	75,333	116,461
Retainage payable	34,620	26,439
Billings in excess of costs and estimated earnings	340,943	362,427
Accrued expenses and other current liabilities	$ 9,892	$ 9,595