Segment Reporting - Information on Long-Lived Assets and Net Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Segment Reporting Information [Line Items]
Property and equipment, net	$ 142,163	$ 101,642
U.S.
Segment Reporting Information [Line Items]
Property and equipment, net	107,216	64,923
Net assets	833,412	763,159
U.K.
Segment Reporting Information [Line Items]
Property and equipment, net	14,023	19,150
Net assets	294,809	196,708
All Other Foreign Countries
Segment Reporting Information [Line Items]
Property and equipment, net	20,924	17,569
Net assets	$ 455,100	$ 440,314