Quarterly report pursuant to Section 13 or 15(d)

Revenue from Contracts with Customers - Summary of Revenue from Contracts (Detail)

v3.22.2.2
Revenue from Contracts with Customers - Summary of Revenue from Contracts (Detail) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended
Sep. 30, 2022
Sep. 30, 2021
Sep. 30, 2022
Sep. 30, 2021
Disaggregation of Revenue [Line Items]        
Net commissions and fees $ 407,551 $ 352,610 $ 1,284,459 $ 1,053,800
Wholesale brokerage [Member]        
Disaggregation of Revenue [Line Items]        
Net commissions and fees 267,222 229,146 841,273 676,229
Binding authorities [Member]        
Disaggregation of Revenue [Line Items]        
Net commissions and fees 55,607 52,795 178,351 161,436
Underwriting management [Member]        
Disaggregation of Revenue [Line Items]        
Net commissions and fees $ 84,722 $ 70,669 $ 264,835 $ 216,135