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Segment Information - Additional Information (Details)
$ in Thousands
3 Months Ended 12 Months Ended
Dec. 31, 2019
USD ($)
Sep. 30, 2019
USD ($)
Jun. 30, 2019
USD ($)
Mar. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Sep. 30, 2018
USD ($)
Jun. 30, 2018
USD ($)
Mar. 31, 2018
USD ($)
Dec. 31, 2019
USD ($)
Segment
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Segment Reporting Information [Line Items]                      
Number of reportable segments | Segment                 4    
Revenues $ 578,989 $ 618,683 $ 575,219 $ 619,280 $ 508,748 $ 530,850 $ 473,187 $ 501,461 $ 2,392,171 $ 2,014,246 $ 1,881,347
London, Bermuda and Cayman Islands                      
Segment Reporting Information [Line Items]                      
Revenues                 $ 17,700 $ 15,200 $ 15,900