Segment Reporting - Revenues Based on Location of Legal Entity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Revenues	$ 2,776,222	$ 2,461,275	$ 2,352,717
U.S.
Segment Reporting Information [Line Items]
Revenues	1,708,673	1,544,777	1,555,133
U.K.
Segment Reporting Information [Line Items]
Revenues	461,354	421,125	389,338
All other foreign countries
Segment Reporting Information [Line Items]
Revenues	$ 606,195	$ 495,373	$ 408,246