Investments - Net Gains (Losses) on Investments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Gain (Loss) on Securities [Line Items]
Net realized gains on investments	$ 20,842	$ 35,826	$ 10,843
Impairment losses due to intent to sell	0	(1,401)	0
Net decrease (increase) in expected credit losses	918	(1,254)	0
Net unrealized gains (losses) on investments	(4,661)	10,960	33,220
Total net gains on investments	17,099	44,131	44,063
Fixed-maturities available for sale
Gain (Loss) on Securities [Line Items]
Fixed-maturities available for sale	5,661	34,869	11,262
Gross investment gains from sales and redemptions	22,766	37,431	17,663
Gross investment losses from sales and redemptions	(17,105)	(2,562)	(6,401)
Trading securities
Gain (Loss) on Securities [Line Items]
Trading securities	390	4	(303)
Equity securities
Gain (Loss) on Securities [Line Items]
Equity securities	10,820	353	(719)
Other investments
Gain (Loss) on Securities [Line Items]
Other investments	$ 3,971	$ 600	$ 603