Contract Assets and Liabilities - Narrative (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Revenue from External Customer [Line Items]
Contract Assets	$ 584,000		$ 560,000
Contract Work in Progress	413,000		571,000
Amount received as payments towards contract assets	557,000		444,000
Contract assets ($291,493 and $295,812 related to VIEs)	996,716		1,130,918
Revenue recognized in contract liabilities	663,000	$ 673,000
Pre-Contract
Revenue from External Customer [Line Items]
Contract assets ($291,493 and $295,812 related to VIEs)	$ 26,000		$ 26,000