Investments - Net Investment Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Schedule Of Investment Income Reported Amounts By Category [Line Items]
Gross investment income	$ 149,854	$ 126,624	$ 91,543
Less investment expenses	(7,576)	(6,241)	(5,465)
Net investment income	142,278	120,383	86,078
Fixed Income Securities
Schedule Of Investment Income Reported Amounts By Category [Line Items]
Gross investment income	120,561	103,446	77,164
Equity Securities
Schedule Of Investment Income Reported Amounts By Category [Line Items]
Gross investment income	13,276	12,238	11,912
Cash, Short-term Investments and Other Invested Assets
Schedule Of Investment Income Reported Amounts By Category [Line Items]
Gross investment income	$ 16,017	$ 10,940	$ 2,467