Investments - Net Gains (Losses) on Investments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Gain (Loss) on Securities [Line Items]
Net realized gains (losses) on investments sold or redeemed	$ (4,139)	$ 14,246	$ (8,454)	$ 18,330
Change in unrealized gains (losses) on investments sold or redeemed	29	(7,584)	(2,914)	(7,115)
Net decrease (increase) in expected credit losses	0	0	0	918
Net unrealized gains (losses) on investments still held	(14,803)	(3,758)	(60,631)	1,290
Total net gains (losses) on investments	(18,913)	2,904	(71,999)	13,423
Net gains (losses) on other financial instruments	2,661	(806)	(15,579)	(845)
Net gains (losses) on investments and other financial instruments	(16,252)	2,098	(87,578)	12,578
Fixed-maturities available for sale
Gain (Loss) on Securities [Line Items]
Gross realized gains	411	5,874	2,554	19,588
Gross realized losses	(4,564)	(1,776)	(12,625)	(13,904)
Fixed-maturities available for sale, net	(4,153)	4,098	(10,071)	5,684
Trading securities
Gain (Loss) on Securities [Line Items]
Net realized gains (losses) on investments sold or redeemed	(30)	0	(136)	391
Net unrealized gains (losses) on investments still held	(7,398)	(2,659)	(27,892)	(6,011)
Equity securities
Gain (Loss) on Securities [Line Items]
Net realized gains (losses) on investments sold or redeemed	0	8,632	1,655	8,405
Net unrealized gains (losses) on investments still held	(7,256)	(1,086)	(32,249)	6,251
Other investments
Gain (Loss) on Securities [Line Items]
Net realized gains (losses) on investments sold or redeemed	44	1,516	98	3,850
Net unrealized gains (losses) on investments still held	$ (149)	$ (13)	$ (490)	$ 1,050