CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Statement of Comprehensive Income [Abstract]
Net income	$ 55,705	$ 60,012	$ 148,526	$ 158,215
Other comprehensive (loss) income, net of tax
Unrealized gain (loss) on debt securities arising during the period	(111,433)	(16,943)	(354,912)	(35,693)
Change in retirement obligation	261	438	861	1,259
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	(70)	0	(86)	0
Other comprehensive income (loss)	(111,242)	(16,505)	(354,137)	(34,434)
Comprehensive income (loss)	$ (55,537)	$ 43,507	$ (205,611)	$ 123,781