Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Statement of Comprehensive Income [Abstract]
Net earnings	$ 29,634	$ 96,527	$ 41,938	$ 194,089
Unrealized gains (losses) on debt securities available-for-sale:
Net unrealized holding gains (losses) arising during period (Note 1)	(71,596)	(368,775)	53,605	(807,191)
Reclassification adjustment for net amounts included in net earnings	(36)	(1,395)	(89)	(4,127)
Net unrealized gains (losses) on securities	(71,632)	(370,170)	53,516	(811,318)
Effect of discount rate changes on liability for future policy benefits (Note 1)	14,344	76,256	(7,370)	156,288
Foreign currency translation adjustments (Note 1)	22	(20)	(8)	295
Benefit plans:
Amortization of net prior service cost and net gain (loss)	(399)	1,134	(798)	2,268
Other comprehensive income (loss)	(57,665)	(292,800)	45,340	(652,467)
Comprehensive income (loss)	$ (28,031)	$ (196,273)	$ 87,278	$ (458,378)