CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 153,051	$ 14,047	$ 303,072	$ 163,852
Other comprehensive income (loss), net of tax:
Change in unrealized investment gains and losses	45,054	143,181	(49,075)	70,596
Benefit plan adjustments	663	1,007	1,536	2,108
Other comprehensive income (loss), net of tax	45,717	144,188	(47,539)	72,704
Comprehensive income	$ 198,768	$ 158,235	$ 255,533	$ 236,556