Supplemental Cash Flow Information - Net Effects of Changes in Operating Assets and Liabilities, Net, on Cash Flows from Operating Activities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Supplemental Cash Flow Elements [Abstract]
Accounts and notes receivable	$ 71,058	$ (214,580)	$ (475,919)
Contract assets	153,832	(12,317)	(92,838)
Inventories	9,860	52,168	(28,131)
Prepaid expenses and other current assets	83,518	(60,475)	(40,187)
Accounts payable and accrued expenses and other non-current liabilities	115,569	39,419	247,897
Contract liabilities	(84,370)	174,230	(23)
Other, net	(22,098)	(135,250)	(11,332)
Net change in operating assets and liabilities, net of non-cash transactions	$ 327,369	(156,805)	$ (400,533)
Payments of on-demand advance payment bonds		87,000
Payments of on-demand performance bonds		$ 25,000