Accumulated Other Comprehensive (Loss) Income - Changes in Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Equity [Abstract]
Unrealized loss on securities, before tax amount	$ (155,758)	$ (27,975)	$ (469,137)	$ (20,796)
Unrealized loss on securities, tax effect	35,373	6,353	106,541	4,723
Unrealized loss on securities, net of tax amount	(120,385)	(21,622)	(362,596)	(16,073)
Reclassification adjustment for securities gain included in net income, before tax amount	(53)		(26)	(33,511)
Reclassification adjustment for securities gain included in net income, tax effect	12		6	7,610
Reclassification adjustment for securities gain included in net income, net of tax amount	(41)	0	(20)	(25,901)
Amortization of net unrealized losses on AFS securities transferred to HTM. before-tax amount	2,139	824	(59,547)	2,787
Amortization of net unrealized losses on AFS securities transferred to HTM, tax	(486)	(187)	13,523	(633)
Amortization of net unrealized losses on AFS securities transferred to HTM, net of tax amount	1,653	637	(46,024)	2,154
Net unrealized loss on interest rate swaps used in cash flow hedges, before-tax amount	(29,053)	(280)	(80,716)	1,215
Net unrealized loss on interest rate swaps used in cash flow hedges, before-tax amount	6,581	64	18,282	(277)
Amount of Gain (Loss) Recognized in OCI on Derivative	(22,472)	(216)	(62,434)	938
Net unrealized losses on interest rate swaps used in cash flow hedges, before-tax amount	3,210	(873)	828	(1,894)
Net unrealized losses on interest rate swaps used in cash flow hedges, tax	(727)	198	(187)	432
Net unrealized losses on interest rate swaps used in cash flow hedges, net of tax amount	2,483	(675)	641	(1,462)
Amortization of net unrecognized pension and postretirement items, before tax amount	33	370	96	1,111
Amortization of net unrecognized pension and postretirement items, tax effect	(8)	(80)	(21)	(243)
Amortization of net unrecognized pension and postretirement items, net of tax amount	25	290	75	868
Total Other Comprehensive Income, Before Tax Amount	(179,482)	(27,934)	(608,502)	(51,088)
Total Other Comprehensive Income, Tax Effect	40,745	6,348	138,144	11,612
Other Comprehensive (Loss)/Income	$ (138,737)	$ (21,586)	$ (470,358)	$ (39,476)