Comprehensive Income/Loss (Comprehensive Income/(Loss) Presented Net of Taxes) (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Equity [Abstract]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, before Tax		$ 274	$ 11,955	$ 32,255	$ 16,527
Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease), after Adjustments, Tax		(77)	(3,365)	(9,074)	(4,652)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax		197	8,590	23,181	11,875
COMPREHENSIVE INCOME
Change in fair value of securities available for sale, pre tax amount		2,332	5,663	14,455	11,841
Change in fair value of securities available for sale, tax (expense) benefit		(637)	(1,269)	(3,413)	(2,718)
Change in fair value of securities available for sale, after tax amount		1,695	4,394	11,042	9,123
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax		0	(1,462)	0	(1,462)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax		0	411	0	411
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax		0	(1,051)	0	(1,051)
Change in fair value of securities available for sale, pre tax amount		2,332	7,125	14,455	13,303
Change in fair value of securities available for sale, tax (expense) benefit		(637)	(1,680)	(3,413)	(3,129)
Change in fair value of securities available for sale, after tax amount		1,695	5,445	11,042	10,174
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax		4,250	12,349	37,817	17,345
Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease), before Adjustments, Tax		(1,195)	(3,476)	(10,638)	(4,882)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax		3,055	8,873	27,179	12,463
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax		3,976	394	5,562	818
Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease), Adjustments, Tax		(1,118)	(111)	(1,564)	(230)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax		2,858	283	3,998	588
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, before Tax		(1)	(11)	(1,390)	(22)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, Tax		0	3	391	6
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, after Tax		(1)	(8)	(999)	(16)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax		246	(2)	491	(4)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, Tax		(69)		(138)	1
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, after Tax		177	(2)	353	(3)
Amortization of certain costs included in net periodic retirement costs, pre tax amount		69	69	138	138
Amortization of certain costs included in net periodic retirement costs, tax (expense) benefit		(20)	(19)	(39)	(39)
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, after Tax		49	50	99	99
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax	[1]	314	56	(761)	112
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax	[1]	(89)	(16)	214	(32)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	[1]	225	40	(547)	80
Total other comprehensive income, pre tax amount		2,920	19,136	45,949	29,942
Total other comprehensive income, tax (expense) benefit		(803)	(5,061)	(12,273)	(7,813)
Total other comprehensive income, after tax amount		$ 2,117	$ 14,075	$ 33,676	$ 22,129

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