Summary of Significant Accounting Policies - Effects of Reclassifications out of Accumulated Other Comprehensive Earnings (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Reclassification Adjustment Out of Accumulated Other Comprehensive Income (Loss)
Earnings before income taxes	$ 159,991	$ 122,791
Income tax (expense) benefit	(32,091)	(23,980)
Net earnings	127,900	98,811
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) - Available-for-sale	(834)	(1,713)
Credit gains (losses) presented within net realized gains	70	(126)
Earnings before income taxes	(764)	(1,839)
Income tax (expense) benefit	160	386
Net earnings	$ (604)	$ (1,453)