Other Comprehensive Income (Loss) - Pretax Components of Other Comprehensive Income (Loss) and Related Income Tax Benefit (Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Components of Other Comprehensive Income (Loss) [Abstract]
Net unrealized investment (losses) gains arising during the period	$ 11,481	$ 179,174	$ (707,005)
Income tax benefit (expense)	(2,411)	(37,626)	148,471
Net of taxes	9,070	141,548	(558,534)
Net changes in benefit plan assets and obligations	24,113	29,978	(54,017)
Income tax benefit (expense)	(5,064)	(6,296)	11,343
Net of taxes	19,049	23,682	(42,674)
Total other comprehensive income (loss)	35,594	209,152	(761,022)
Total income tax benefit (expense)	(7,475)	(43,922)	159,814
Other comprehensive income (loss), net of tax	$ 28,119	$ 165,230	$ (601,208)