Investments - Net Investment Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Schedule Of Investment Income Reported Amounts By Category [Line Items]
Gross investment income	$ 91,543	$ 75,050	$ 72,862
Less investment expenses	(5,465)	(6,188)	(4,969)
Net investment income	86,078	68,862	67,893
Fixed Income Securities
Schedule Of Investment Income Reported Amounts By Category [Line Items]
Gross investment income	77,164	60,624	59,755
Equity Securities
Schedule Of Investment Income Reported Amounts By Category [Line Items]
Gross investment income	11,912	11,787	9,728
Cash, Short-term Investments and Other Invested Assets
Schedule Of Investment Income Reported Amounts By Category [Line Items]
Gross investment income	$ 2,467	$ 2,639	$ 3,379