Investments - Schedule of Realized Gains and Losses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Investments [Abstract]
Fixed maturity securities, gross realized gains	$ 0	$ 0
Fixed maturity securities, gross realized losses	(311)	(7)
Fixed maturity securities	(311)	(7)
Bank loan participations, gross realized gains	308	20
Bank loan participations, gross realized losses	(948)	(423)
Changes in fair values of bank loan participations	359	910
Bank loan participations	(281)	507
Equity securities, gross realized gain	1,124	581
Equity securities, gross realized losses	(177)	(267)
Changes in fair values of equity securities	4,228	(643)
Equity securities	5,175	(329)
Short-term investments and other, gross realized gains	0	2
Short-term investments and other, gross realized losses	0	(13)
Changes in fair values of short-term investments and other	0	0
Short-term investments and other	0	(11)
Total	$ 4,583	$ 160