Comprehensive Income/Loss (Comprehensive Income/(Loss) Presented Net of Taxes) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Equity [Abstract]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, before Tax		$ 4,216	$ (564)	$ 20,743	$ (425)
Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease), after Adjustments, Tax		(1,186)	159	(5,838)	123
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax		3,030	(405)	14,905	(302)
COMPREHENSIVE INCOME
Change in fair value of securities available for sale, pre tax amount		2,858	(2,988)	14,699	(12,761)
Change in fair value of securities available for sale, tax (expense) benefit		(683)	726	(3,401)	3,107
Change in fair value of securities available for sale, after tax amount		2,175	(2,262)	11,298	(9,654)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax		0	0	(1,462)	0
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Tax		0	0	411	0
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax		0	0	(1,051)	0
Change in fair value of securities available for sale, pre tax amount		2,858	(2,988)	16,161	(12,761)
Change in fair value of securities available for sale, tax (expense) benefit		(683)	726	(3,812)	3,107
Change in fair value of securities available for sale, after tax amount		2,175	(2,262)	12,349	(9,654)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax		4,568	(296)	21,913	100
Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease), before Adjustments, Tax		(1,285)	83	(6,167)	(25)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax		3,283	(213)	15,746	75
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax		352	268	1,170	525
Other Comprehensive Income (Loss), Derivative, Excluded Component, Increase (Decrease), Adjustments, Tax		(99)	(76)	(329)	(148)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax		253	192	841	377
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, before Tax		(11)		(33)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, Tax		3		9
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, after Tax		(8)		(24)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax		(2)	94	(6)	281
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, Tax		1	(26)	2	(79)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, after Tax		(1)	68	(4)	202
Amortization of certain costs included in net periodic retirement costs, pre tax amount		69	69	207	207
Amortization of certain costs included in net periodic retirement costs, tax (expense) benefit		(19)	(20)	(58)	(58)
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, after Tax		50	49	149	149
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax	[1]	56	163	168	488
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax	[1]	(15)	(46)	(47)	(137)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	[1]	41	117	121	351
Total other comprehensive income, pre tax amount		7,130	(3,389)	37,072	(12,698)
Total other comprehensive income, tax (expense) benefit		(1,884)	839	(9,697)	3,093
Total other comprehensive income, after tax amount		$ 5,246	$ (2,550)	$ 27,375	$ (9,605)

[1] The amortization of prior service costs is included in the computation of net periodic pension cost as disclosed in the Employee Benefit Plans footnote in the Company's Annual Report on Form 10-K for the year ended December 31, 2018, filed with the Securities and Exchange Commission.