Comprehensive Income/Loss (Comprehensive Income/(Loss) Presented Net of Taxes) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2022	Mar. 31, 2021
Equity [Abstract]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, before Tax		$ (24,985)	$ (9,159)
Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease), after Adjustments, Tax		7,035	2,576
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax		(17,950)	(6,583)
COMPREHENSIVE INCOME
Change in fair value of securities available for sale, pre tax amount		(81,619)	(10,361)
Change in fair value of securities available for sale, tax (expense) benefit		19,063	2,587
Change in fair value of securities available for sale, after tax amount		(62,556)	(7,774)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax		0	0
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax		0	0
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax		0	0
Change in fair value of securities available for sale, pre tax amount		(81,619)	(10,361)
Change in fair value of securities available for sale, tax (expense) benefit		19,063	2,587
Change in fair value of securities available for sale, after tax amount		(62,556)	(7,774)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax		(20,480)	(4,779)
Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease), before Adjustments, Tax		5,768	1,344
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax		(14,712)	(3,435)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax		4,505	4,380
Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease), Adjustments, Tax		(1,267)	(1,232)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax		3,238	3,148
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Loss on Termination of Derivatives, before Tax		0	0
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, before Tax			653
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, Tax			(184)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, after Tax			469
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax		159	442
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, Tax		(45)	(124)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, after Tax		114	318
Amortization of certain costs included in net periodic retirement costs, pre tax amount		10	44
Amortization of certain costs included in net periodic retirement costs, tax (expense) benefit		(3)	(12)
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, after Tax		7	32
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax	[1]	169	1,139
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax	[1]	(48)	(320)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	[1]	121	819
Total other comprehensive income, pre tax amount		(106,435)	(18,381)
Total other comprehensive income, tax (expense) benefit		26,050	4,843
Total other comprehensive income, after tax amount		(80,385)	(13,538)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Loss on Termination of Derivatives, before Tax		$ 0	$ 0

[1] The amortization of prior service costs is included in the computation of net periodic pension cost as disclosed in Note 14 "Employee Benefit Plans" within the Notes to the Consolidated Financial Statements included in Item 8 of the Company's 2021 Form 10-K.