Other Comprehensive Income (Loss) (Activity in Other Comprehensive Income) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract]
Changes in fair value of securities available for sale, before tax		$ (5,924)	$ 1,736	$ (23,605)	$ 5,274
Changes in fair value of securities available for sale, tax		(1,393)	642	(5,548)	1,951
Changes in fair value of securities available for sale		(4,531)	1,094	(18,057)	3,323
Net gains on securities reclassified into earnings, before tax		0	0	0	0
Net gains on securities reclassified into earnings, tax		0	0	0	0
Net gains on securities reclassified into earnings		0	0	0	0
Net change in fair value of securities available for sale, before tax		(5,924)	1,736	(23,605)	5,274
Net change in fair value of securities available for sale, tax		(1,393)	642	(5,548)	1,951
Net change in fair value of securities available for sale		(4,531)	1,094	(18,057)	3,323
Change in fair value of cash flow hedges, before tax		(626)	(237)	632	(1,064)
Change in fair value of cash flow hedges, tax		(148)	(83)	50	(361)
Change in fair value of cash flow hedges		(478)	(154)	582	(703)
Net cash flow hedge losses reclassified into earnings, before tax	[1]	830	224	1,082	539
Net cash flow hedge losses reclassified into earnings, tax	[1]	197	83	255	200
Net cash flow hedge losses reclassified into earnings	[1]	633	141	827	339
Net change in fair value of cash flow hedges, before tax		204	(13)	1,714	(525)
Net change in fair value of cash flow hedges, tax		49	0	305	(161)
Net change in fair value of cash flow hedges		155	(13)	1,409	(364)
Defined benefit plan obligation adjustment, before tax		0	0	0	(407)
Defined benefit plan obligation adjustment, tax		0	0	0	(150)
Defined benefit plan obligation adjustment		0	0	0	(257)
Amortization of net actuarial losses, before tax	[2]	477	355	1,430	1,105
Amortization of net actuarial losses, tax	[2]	112	134	337	411
Amortization of net actuarial losses	[2]	365	221	1,093	694
Amortization of net prior service credits, before tax	[2]	(6)	(6)	(17)	(17)
Amortization of net prior service credits, tax	[2]	(2)	(2)	(5)	(7)
Amortization of net prior service credits	[2]	(4)	(4)	(12)	(10)
Net change in defined benefit plan obligations, before tax		471	349	1,413	681
Net change in defined benefit plan obligations, tax		110	132	332	254
Net change in defined benefit plan obligations		361	217	1,081	427
Total other comprehensive income (loss), before tax		(5,249)	2,072	(20,478)	5,430
Total other comprehensive income (loss), tax		(1,234)	774	(4,911)	2,044
Total other comprehensive income (loss), net of tax		$ (4,015)	$ 1,298	$ (15,567)	$ 3,386

[1] The pre-tax amounts are included in interest expense on FHLB advances, interest expense on junior subordinated debentures and interest and fees on loans in the Unaudited Consolidated Statements of Income.

[2] The pre-tax amounts are included in other expenses in the Unaudited Consolidated Statements of Income.