Investments - Schedule of Gross Unrealized Losses and Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Fixed maturity securities
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, less than 12 months, fair value	$ 1,283,923	$ 596,444
Fixed maturity securities, less than 12 months, gross unrealized losses	(109,477)	(11,018)
Fixed maturity securities, 12 months or more, fair value	161,387	21,161
Fixed maturity securities, 12 months or more, gross unrealized losses	(22,625)	(1,539)
Fixed maturity securities, fair value	1,445,310	617,605
Fixed maturity securities, gross unrealized losses	(132,102)	(12,557)
State and municipal
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, less than 12 months, fair value	264,848	93,313
Fixed maturity securities, less than 12 months, gross unrealized losses	(37,476)	(2,162)
Fixed maturity securities, 12 months or more, fair value	6,707	1,150
Fixed maturity securities, 12 months or more, gross unrealized losses	(1,422)	(50)
Fixed maturity securities, fair value	271,555	94,463
Fixed maturity securities, gross unrealized losses	(38,898)	(2,212)
Residential mortgage-backed
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, less than 12 months, fair value	207,169	140,386
Fixed maturity securities, less than 12 months, gross unrealized losses	(16,405)	(2,337)
Fixed maturity securities, 12 months or more, fair value	45,750	147
Fixed maturity securities, 12 months or more, gross unrealized losses	(5,839)	(2)
Fixed maturity securities, fair value	252,919	140,533
Fixed maturity securities, gross unrealized losses	(22,244)	(2,339)
Corporate
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, less than 12 months, fair value	475,416	179,078
Fixed maturity securities, less than 12 months, gross unrealized losses	(37,398)	(4,232)
Fixed maturity securities, 12 months or more, fair value	68,605	18,635
Fixed maturity securities, 12 months or more, gross unrealized losses	(12,462)	(1,482)
Fixed maturity securities, fair value	544,021	197,713
Fixed maturity securities, gross unrealized losses	(49,860)	(5,714)
Commercial mortgage and asset-backed
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, less than 12 months, fair value	288,044	159,289
Fixed maturity securities, less than 12 months, gross unrealized losses	(16,986)	(1,695)
Fixed maturity securities, 12 months or more, fair value	23,225	1,229
Fixed maturity securities, 12 months or more, gross unrealized losses	(1,248)	(5)
Fixed maturity securities, fair value	311,269	160,518
Fixed maturity securities, gross unrealized losses	(18,234)	(1,700)
U.S. Treasury securities and obligations guaranteed by the U.S. government
Debt Securities, Available-for-sale [Line Items]
Fixed maturity securities, less than 12 months, fair value	48,446	24,378
Fixed maturity securities, less than 12 months, gross unrealized losses	(1,212)	(592)
Fixed maturity securities, 12 months or more, fair value	17,100	0
Fixed maturity securities, 12 months or more, gross unrealized losses	(1,654)	0
Fixed maturity securities, fair value	65,546	24,378
Fixed maturity securities, gross unrealized losses	$ (2,866)	$ (592)

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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