Investments - Schedule of Net Investment Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Marketable Securities [Line Items]
Gross investment income	$ 15,336	$ 11,713	$ 42,113	$ 28,495
Investment expenses	(298)	(222)	(839)	(567)
Net investment income	15,038	11,491	41,274	27,928
U.S. government and government agency
Marketable Securities [Line Items]
Gross investment income	1,562	3,793	5,040	11,316
State and municipal
Marketable Securities [Line Items]
Gross investment income	1,058	467	2,621	1,241
Commercial mortgage-backed securities
Marketable Securities [Line Items]
Gross investment income	1,417	761	3,864	1,603
Residential mortgage-backed securities
Marketable Securities [Line Items]
Gross investment income	3,489	1,955	9,157	4,118
Asset-backed securities
Marketable Securities [Line Items]
Gross investment income	1,673	719	4,725	1,760
Corporate
Marketable Securities [Line Items]
Gross investment income	4,716	1,611	12,212	3,614
Short-term investments
Marketable Securities [Line Items]
Gross investment income	0	134	214	350
Cash and cash equivalents
Marketable Securities [Line Items]
Gross investment income	$ 1,421	$ 2,273	$ 4,280	$ 4,493