Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Statement Of Income And Comprehensive Income [Abstract]
Net Income	$ 52,801	$ 62,053	$ 164,497	$ 189,535
Other Comprehensive Loss, Net of Tax:
Net Unrealized Losses on Investment Securities	(79,600)	(7,541)	(382,371)	(57,714)
Defined Benefit Plans	354	441	1,059	1,324
Total Other Comprehensive Loss	(79,246)	(7,100)	(381,312)	(56,390)
Comprehensive Income (Loss)	$ (26,445)	$ 54,953	$ (216,815)	$ 133,145