Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Statement Of Income And Comprehensive Income [Abstract]
Net Income	$ 56,862	$ 67,533	$ 111,696	$ 127,482
Other Comprehensive Income (Loss), Net of Tax:
Net Unrealized Losses on Investment Securities	(122,647)	(123)	(302,771)	(50,173)
Defined Benefit Plans	352	442	705	883
Total Other Comprehensive Income (Loss)	(122,295)	319	(302,066)	(49,290)
Comprehensive Income (Loss)	$ (65,433)	$ 67,852	$ (190,370)	$ 78,192