CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Statement of Comprehensive Income [Abstract]
Net income	$ 63,061	$ 55,705	$ 199,131	$ 148,526
Other comprehensive (loss) income, net of tax
Unrealized gain (loss) on debt securities arising during the period	(55,397)	(111,433)	(49,808)	(354,912)
Change in retirement obligation	164	261	411	861
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax	(1,493)	0	(1,824)	0
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax	(269)	(70)	(121)	(86)
Other comprehensive income (loss)	(56,995)	(111,242)	(51,342)	(354,137)
Comprehensive income (loss)	$ 6,066	$ (55,537)	$ 147,789	$ (205,611)