Fair Value Measurements - Schedule of the Carrying Value and Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024	Mar. 31, 2024	Dec. 31, 2023
Assets
Fixed maturity securities, available-for-sale	$ 1,259,627	$ 1,189,733
Equity securities	87,746	86,479
Bank loan participations	144,014	142,410
Cash and cash equivalents	279,427	362,345
Restricted cash equivalents	29,012	28,705	$ 73,396	$ 72,449
Short-term investments	79,091	97,074
Liabilities
Senior debt	225,800	200,800
Junior subordinated debt	104,055	104,055
Carrying Value
Assets
Fixed maturity securities, available-for-sale	1,259,627	1,189,733
Equity securities	87,746	86,479
Bank loan participations	144,014	142,410
Cash and cash equivalents	279,427	362,345
Restricted cash equivalents	29,012	28,705
Short-term investments	79,091	97,074
Other invested assets – notes receivable	28,430	13,902
Liabilities
Senior debt	225,800	200,800
Junior subordinated debt	104,055	104,055
Fair Value
Assets
Fixed maturity securities, available-for-sale	1,259,627	1,189,733
Equity securities	87,746	86,479
Bank loan participations	144,014	142,410
Cash and cash equivalents	279,427	362,345
Restricted cash equivalents	29,012	28,705
Short-term investments	79,091	97,074
Other invested assets – notes receivable	28,692	12,877
Liabilities
Senior debt	226,366	201,787
Junior subordinated debt	$ 121,480	$ 121,766