Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Statement of Comprehensive Income [Abstract]
Net Income	$ 70,871	$ 75,583	$ 205,148	$ 213,611
Other Comprehensive (Loss)/Income, net of tax:
Unrealized (loss)/gain on securities	(120,385)	(21,622)	(362,596)	(16,073)
Reclassification adjustment for securities gains included in net income	(41)	0	(20)	(25,901)
Amortization of net unrealized losses on AFS securities transferred to HTM	1,653	637	(46,024)	2,154
Net unrealized gains (losses) on AFS investment securities	(118,773)	(20,985)	(408,640)	(39,820)
Net unrealized holding (losses) gains arising during the period	(22,472)	(216)	(62,434)	938
Reclassification adjustment for net (losses) gains realized in net income	2,483	(675)	641	(1,462)
Net unrealized (losses) gains on interest rate swaps used in cash flow hedges	(19,989)	(891)	(61,793)	(524)
Amortization of net unrecognized pension and postretirement items	25	290	75	868
Other Comprehensive (Loss)/Income	(138,737)	(21,586)	(470,358)	(39,476)
Total Comprehensive (Loss) Income	$ (67,866)	$ 53,997	$ (265,210)	$ 174,135