Segment Information - Additional Information (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020 USD ($)	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2020 USD ($) Segment	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | Segment									4
Revenues	$ 642,111	$ 673,962	$ 598,806	$ 698,495	$ 578,989	$ 618,683	$ 575,219	$ 619,280	$ 2,613,375	$ 2,392,171	$ 2,014,246
London, Bermuda and Cayman Islands
Segment Reporting Information [Line Items]
Revenues									$ 35,100	$ 17,700	$ 15,200