Summary of Significant Accounting Policies - Schedule of Revenue Calculated under Old and New Accounting Methods (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Revenue	$ 1,337,973
Contract assets	126,688	$ 123,197
Contract liabilities	33,494	38,571
ASU 2014-09 | As Reported
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Revenue	1,337,973
Contract assets	126,688	123,197
Contract liabilities	$ 33,494	$ 38,571