Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Statement of Comprehensive Income [Abstract]
Net Income	$ 286,981	$ 275,497	$ 178,040
Unrealized gains (losses) on AFS investment securities:
Unrealized gains (losses) on securities	(312,169)	(17,948)	65,651
Reclassification adjustment for securities gains (losses) included in net income	(20)	(25,905)	(2,359)
Amortization of net unrealized gains (losses) on AFS securities transferred to HTM	(44,483)	2,690	3,448
Net unrealized gains (losses) on AFS investment securities	(356,672)	(41,163)	66,740
Net unrealized holding gains (losses) arising during the period	(62,963)	(2,670)	0
Reclassification adjustment for net loss (gain) realized in net income on interest rate derivatives used in cash flow hedges	6,004	(2,147)	0
Net unrealized gains (losses) on interest rate derivatives used in cash flow hedges	(56,959)	(4,817)	0
Defined benefit pension plan and postretirement benefits:
Unrecognized pension and postretirement income (cost)	644	7,144	(2,532)
Amortization of net unrecognized pension and postretirement income (loss)	100	1,156	1,020
Net unrealized (losses) gains on defined benefit pension and postretirement plans	744	8,300	(1,512)
Other Comprehensive Income (Loss)	(412,887)	(37,680)	65,228
Total Comprehensive Income (Loss)	$ (125,906)	$ 237,817	$ 243,268