Investments - Summarized Fair Value and Gross Unrealized Losses on Securities Available for Sale (Details) $ in Thousands	Jun. 30, 2022 USD ($) security	Dec. 31, 2021 USD ($) security
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, Number of issues | security	323	404
Less than 12 months, Fair value	$ 410,454	$ 682,402
Less than 12 months, Unrealized losses	$ (36,342)	$ (13,818)
12 months or longer, Number of issues | security	174	33
12 months or longer, Fair value	$ 258,786	$ 45,645
12 months or longer, Unrealized losses	$ (39,794)	$ (1,853)
Fixed Maturities | U.S. government obligations and agencies
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, Number of issues | security	3	4
Less than 12 months, Fair value	$ 11,554	$ 18,913
Less than 12 months, Unrealized losses	$ (80)	$ (111)
12 months or longer, Number of issues | security	5	4
12 months or longer, Fair value	$ 9,058	$ 5,016
12 months or longer, Unrealized losses	$ (711)	$ (223)
Fixed Maturities | Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, Number of issues | security	175	249
Less than 12 months, Fair value	$ 230,149	$ 378,595
Less than 12 months, Unrealized losses	$ (23,682)	$ (7,468)
12 months or longer, Number of issues | security	95	18
12 months or longer, Fair value	$ 113,327	$ 17,356
12 months or longer, Unrealized losses	$ (17,574)	$ (679)
Fixed Maturities | Mortgage-backed and asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, Number of issues | security	131	145
Less than 12 months, Fair value	$ 157,635	$ 274,883
Less than 12 months, Unrealized losses	$ (11,032)	$ (5,969)
12 months or longer, Number of issues | security	73	11
12 months or longer, Fair value	$ 133,065	$ 23,273
12 months or longer, Unrealized losses	$ (20,840)	$ (951)
Fixed Maturities | Municipal bonds
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, Number of issues | security	9	5
Less than 12 months, Fair value	$ 9,655	$ 9,811
Less than 12 months, Unrealized losses	$ (1,265)	$ (269)
12 months or longer, Number of issues | security	1	0
12 months or longer, Fair value	$ 3,336	$ 0
12 months or longer, Unrealized losses	$ (669)	$ 0
Fixed Maturities | Redeemable preferred stock
Debt Securities, Available-for-sale [Line Items]
Less than 12 months, Number of issues | security	5	1
Less than 12 months, Fair value	$ 1,461	$ 200
Less than 12 months, Unrealized losses	$ (283)	$ (1)
12 months or longer, Number of issues | security	0	0
12 months or longer, Fair value	$ 0	$ 0
12 months or longer, Unrealized losses	$ 0	$ 0