CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Comprehensive Income [Abstract]
Net income	$ 712,949	$ 865,349	$ 634,983
Other comprehensive income (loss), net of tax:
Change in unrealized investment gains and losses	141,548	(558,534)	(122,099)
Benefit plans adjustment	23,682	(42,674)	24,975
Other comprehensive income (loss), net of tax	165,230	(601,208)	(97,124)
Comprehensive income	$ 878,179	$ 264,141	$ 537,859