Summary of Significant Accounting Policies - Schedule of Effects of Reclassifications out of Accumulated Other Comprehensive Earnings (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Reclassification Adjustment Out of Accumulated Other Comprehensive Income (Loss)
Net realized gains (losses)	$ 12,804		$ 36,463		$ 18,392	$ 50,613
Earnings (loss) before income taxes	(6,554)		102,021		51,971	191,855
Income tax (expense) benefit	4,315		(20,206)		(6,287)	(37,028)
Net earnings (loss)	(2,239)	$ 47,923	81,815	$ 73,012	45,684	154,827
Unrealized Gains and Losses on Available-for-Sale Securities | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment Out of Accumulated Other Comprehensive Income (Loss)
Net realized gains (losses)	(722)		366		(772)	1,549
Credit gains presented within net realized gains	303		171		149	193
Earnings (loss) before income taxes	(419)		537		(623)	1,742
Income tax (expense) benefit	88		(113)		131	(366)
Net earnings (loss)	$ (331)		$ 424		$ (492)	$ 1,376