Segment Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2024 USD ($) segment	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Segment Reporting [Abstract]
Number of reportable segments | segment	1
Schedule of Segment Reporting Information, by Segment [Table]
Total operating revenue	$ 3,795,115	$ 3,268,940	$ 2,840,124
Total operating expenses	3,118,660	2,748,684	2,463,910
Operating income	676,455	520,256	376,214
Total investment income	69,260	28,968	632
Interest expense, net	0	0	2,009
Other income	11,564	12,712	1,615
Income tax expense	156,965	115,875	77,883
Net income	600,314	446,061	298,569
Management fee revenue - administrative services
Schedule of Segment Reporting Information, by Segment [Table]
Total operating revenue	68,355	63,669	58,323
Administrative services reimbursement revenue
Schedule of Segment Reporting Information, by Segment [Table]
Total operating revenue	806,336	737,139	668,268
Total operating expenses	806,336	737,139	668,268
Service agreement revenue
Schedule of Segment Reporting Information, by Segment [Table]
Total operating revenue	26,350	26,059	25,687
Management fee revenue - policy issuance and renewal services
Schedule of Segment Reporting Information, by Segment [Table]
Total operating revenue	2,894,074	2,442,073	2,087,846
Total operating expenses	2,312,324	2,011,545	1,795,642
Management Operations
Schedule of Segment Reporting Information, by Segment [Table]
Total operating revenue	3,795,115	3,268,940	2,840,124
Commissions	1,601,401	1,348,530	1,179,569
Underwriting and policy processing	199,485	181,003	171,625
Information technology	215,488	216,746	198,157
Sales and advertising	66,480	58,905	60,000
Customer service	43,045	34,391	34,333
Administrative and other	186,425	171,970	151,958
Total operating expenses	3,118,660	2,748,684	2,463,910
Operating income	676,455	520,256	376,214
Total investment income	69,260	28,968	632
Interest expense, net	0	0	2,009
Other income	11,564	12,712	1,615
Income tax expense	156,965	115,875	77,883
Net income	600,314	446,061	298,569
Management Operations | Administrative services reimbursement revenue
Schedule of Segment Reporting Information, by Segment [Table]
Total operating revenue	806,336	737,139	668,268
Total operating expenses	806,336	737,139	668,268
Management Operations | Service agreement revenue
Schedule of Segment Reporting Information, by Segment [Table]
Total operating revenue	26,350	26,059	25,687
Management Operations | Management fee revenue - policy issuance and renewal services
Schedule of Segment Reporting Information, by Segment [Table]
Total operating expenses	2,312,324	2,011,545	1,795,642
Management Operations | Management fee revenue
Schedule of Segment Reporting Information, by Segment [Table]
Total operating revenue	$ 2,962,429	$ 2,505,742	$ 2,146,169