CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Statement of Comprehensive Income [Abstract]
Net income	$ 175,013	$ 150,021
Other comprehensive income (loss), net of tax:
Change in unrealized investment gains and losses	(270,938)	(94,129)
Benefit plan adjustments	393	873
Other comprehensive income (loss), net of tax	(270,545)	(93,256)
Comprehensive income (loss)	$ (95,532)	$ 56,765