Accounts Receivable - Schedule of Accounts Receivable (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross accounts receivable	$ 668,190	$ 661,874
Allowances for current expected credit losses and other reserves	(1,654)	(1,822)
Accounts receivable, net	666,536	660,052
Unbilled accounts receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross accounts receivable	187,266	188,400
Trade accounts receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross accounts receivable	$ 480,924	$ 473,474