CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 865,349	$ 634,983	$ 446,093
Other comprehensive income (loss), net of tax:
Change in unrealized investment gains and losses	(558,534)	(122,099)	133,616
Benefit plans adjustment	(42,674)	24,975	10,497
Other comprehensive income (loss), net of tax	(601,208)	(97,124)	144,113
Comprehensive income	$ 264,141	$ 537,859	$ 590,206