Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Statement Of Income And Comprehensive Income [Abstract]
Net Income	$ 225,804	$ 253,372	$ 153,804
Other Comprehensive Income (Loss), Net of Tax:
Net Unrealized Gains (Losses) on Investment Securities	(376,694)	(83,958)	43,428
Defined Benefit Plans	8,418	9,754	(4,494)
Other Comprehensive Income (Loss)	(368,276)	(74,204)	38,934
Comprehensive Income (Loss)	$ (142,472)	$ 179,168	$ 192,738