Consolidated Statements of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Supplemental Cash Flow Elements [Abstract]
Accounts receivable	$ (104,901)	$ (81,983)	$ 3,899
Retainage receivable	(85,769)	(78,520)	56,754
Costs and estimated earnings in excess of billings	(113,190)	18,751	(209,537)
Other current assets	(49,468)	(76,146)	15,398
Accounts payable	111,912	53,999	(78,243)
Retainage payable	62,954	35,013	(49,864)
Billings in excess of costs and estimated earnings	(5,168)	245,292	76,703
Accrued expenses and other current liabilities	13,654	14,851	28,046
Changes in other components of working capital	(169,976)	131,257	(156,844)
Interest	57,038	56,137	51,063
Income taxes	11,204	43,374	13,652
Supplemental disclosure of non-cash investing activities:
Real property acquired in settlement of a receivable	$ 11,660	$ 0	$ 0