Revenue - Schedule of Disaggregated Revenue (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Disaggregation of Revenue [Line Items]
Commissions and fees	$ 376,249	$ 337,103	$ 786,780	$ 715,199
Investment income	2,562	2,737	5,436	5,008
Total revenues	378,811	339,840	792,216	720,207
Direct Bill Revenue
Disaggregation of Revenue [Line Items]
Commissions and fees	134,200	132,700	343,100	335,300
Agency Bill Revenue
Disaggregation of Revenue [Line Items]
Commissions and fees	165,000	147,700	295,000	267,500
Commission Revenue
Disaggregation of Revenue [Line Items]
Commissions and fees	299,243	280,405	638,105	602,780
Profit Sharing Revenue
Disaggregation of Revenue [Line Items]
Commissions and fees	19,960	22,285	44,300	42,972
Consulting and Service Fee Revenue
Disaggregation of Revenue [Line Items]
Commissions and fees	27,375	18,621	47,531	38,754
Policy Fee and Installment Fee Revenue
Disaggregation of Revenue [Line Items]
Commissions and fees	19,684	14,642	37,664	27,250
Assumed premium earned
Disaggregation of Revenue [Line Items]
Commissions and fees	5,488	0	9,805	0
Other Income
Disaggregation of Revenue [Line Items]
Commissions and fees	$ 4,499	$ 1,150	$ 9,375	$ 3,443