Segment Information - Additional Information (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) Segment	Sep. 30, 2019 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | Segment			4
Revenues	$ 673,962	$ 618,683	$ 1,971,264	$ 1,813,182
London, Bermuda and Cayman Islands
Segment Reporting Information [Line Items]
Revenues	$ 9,100	$ 4,400	$ 25,400	$ 12,400