Segment Information - Schedule of Segment Reporting Information, by Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Segment Reporting Information [Line Items]
Total operating revenue	$ 4,067,258	$ 3,795,115	$ 3,268,940
Total operating expenses	3,350,074	3,118,660	2,748,684
Operating income	717,184	676,455	520,256
Total investment income	84,861	69,260	28,968
Other income	8,558	11,564	12,712
Contribution to charitable foundation	100,000	0	0
Income tax expense	151,268	156,965	115,875
Net income	559,335	600,314	446,061
Management Operations
Segment Reporting Information [Line Items]
Total operating revenue	4,067,258	3,795,115	3,268,940
Commissions	1,777,043	1,601,401	1,348,530
Underwriting and policy processing	204,245	199,485	181,003
Information technology	239,789	215,488	216,746
Sales and advertising	66,475	66,480	58,905
Customer service	46,538	43,045	34,391
Administrative and other	179,345	186,425	171,970
Total operating expenses	3,350,074	3,118,660	2,748,684
Operating income	717,184	676,455	520,256
Total investment income	84,861	69,260	28,968
Other income	8,558	11,564	12,712
Income tax expense	151,268	156,965	115,875
Net income	559,335	600,314	446,061
Management fee revenue | Management Operations
Segment Reporting Information [Line Items]
Total operating revenue	3,205,864	2,962,429	2,505,742
Administrative services reimbursement revenue
Segment Reporting Information [Line Items]
Total operating revenue	836,639	806,336	737,139
Total operating expenses	836,639	806,336	737,139
Administrative services reimbursement revenue | Management Operations
Segment Reporting Information [Line Items]
Total operating revenue	836,639	806,336	737,139
Total operating expenses	836,639	806,336	737,139
Service agreement revenue
Segment Reporting Information [Line Items]
Total operating revenue	24,755	26,350	26,059
Service agreement revenue | Management Operations
Segment Reporting Information [Line Items]
Total operating revenue	24,755	26,350	26,059
Cost of operations - policy issuance and renewal services
Segment Reporting Information [Line Items]
Total operating revenue	3,131,806	2,894,074	2,442,073
Total operating expenses	2,513,435	2,312,324	2,011,545
Cost of operations - policy issuance and renewal services | Management Operations
Segment Reporting Information [Line Items]
Total operating expenses	$ 2,513,435	$ 2,312,324	$ 2,011,545