Summary of Significant Accounting Policies - Schedule of Effects of Reclassifications out of Accumulated Other Comprehensive Earnings (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Reclassification Adjustment Out of Accumulated Other Comprehensive Income (Loss)
Net realized gains (losses)	$ 5,588	$ 14,150
Earnings before income taxes	58,525	89,834
Income tax (expense) benefit	(10,602)	(16,822)
Net earnings	47,923	73,012
Unrealized Gains and Losses on Available-for-Sale Securities | Reclassification out of Accumulated Other Comprehensive Income (Loss)
Reclassification Adjustment Out of Accumulated Other Comprehensive Income (Loss)
Net realized gains (losses)	(51)	1,183
Credit gains (losses) presented within net realized gains	(153)	22
Earnings before income taxes	(204)	1,205
Income tax (expense) benefit	43	(253)
Net earnings	$ (161)	$ 952