Summary of Significant Accounting Policies - Changes in the Balance of Each Component of Accumulated Other Comprehensive Earnings (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2024	Jun. 30, 2023
Changes in the balance of each component of accumulated other comprehensive earnings (loss)
Beginning balance		$ (166,303)			$ (166,303)
Other comprehensive earnings (loss)	$ (7,843)	(12,671)	$ (19,721)	$ 37,707	(20,514)	$ 17,986
Ending balance	(186,817)				(186,817)
Unrealized Gains and Losses on Available-for-Sale Securities
Changes in the balance of each component of accumulated other comprehensive earnings (loss)
Beginning balance	(178,974)	(166,303)	(191,369)	(229,076)	(166,303)	(229,076)
Other comprehensive earnings (loss) before reclassifications	(8,571)		(20,347)		(21,846)	15,908
Amounts reclassified from accumulated other comprehensive earnings	728		626		1,332	2,078
Other comprehensive earnings (loss)	(7,843)		(19,721)		(20,514)	17,986
Ending balance	(186,817)	$ (178,974)	(211,090)	$ (191,369)	(186,817)	(211,090)
Balance of securities for which an allowance for credit losses has been recognized in net earnings	$ 1,463		$ 1,053		$ 1,463	$ 1,053