Other Comprehensive Income (Loss) (Activity in Other Comprehensive Income) (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 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		$ (4,068)	$ 2,902	$ (17,681)	$ 3,538
Changes in fair value of securities available for sale, tax		(956)	1,074	(4,155)	1,309
Changes in fair value of securities available for sale		(3,112)	1,828	(13,526)	2,229
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		(4,068)	2,902	(17,681)	3,538
Net change in fair value of securities available for sale, tax		(956)	1,074	(4,155)	1,309
Net change in fair value of securities available for sale		(3,112)	1,828	(13,526)	2,229
Change in fair value of cash flow hedges, before tax		455	(853)	1,258	(827)
Change in fair value of cash flow hedges, tax		107	(292)	198	(278)
Change in fair value of cash flow hedges		348	(561)	1,060	(549)
Net cash flow hedge losses reclassified into earnings, before tax	[1]	21	180	252	316
Net cash flow hedge losses reclassified into earnings, tax	[1]	4	67	58	117
Net cash flow hedge losses reclassified into earnings	[1]	17	113	194	199
Net change in fair value of cash flow hedges, before tax		476	(673)	1,510	(511)
Net change in fair value of cash flow hedges, tax		111	(225)	256	(161)
Net change in fair value of cash flow hedges		365	(448)	1,254	(350)
Defined benefit plan obligation adjustment, before tax		0	(407)	0	(407)
Defined benefit plan obligation adjustment, tax		0	(150)	0	(150)
Defined benefit plan obligation adjustment		0	(257)	0	(257)
Amortization of net actuarial losses, before tax	[2]	477	406	953	750
Amortization of net actuarial losses, tax	[2]	113	149	225	276
Amortization of net actuarial losses	[2]	364	257	728	474
Amortization of net prior service credits, before tax	[2]	(5)	(5)	(11)	(11)
Amortization of net prior service credits, tax	[2]	(1)	(1)	(3)	(3)
Amortization of net prior service credits	[2]	(4)	(4)	(8)	(8)
Net change in defined benefit plan obligations, before tax		472	(6)	942	332
Net change in defined benefit plan obligations, tax		112	(2)	222	123
Net change in defined benefit plan obligations		360	(4)	720	209
Total other comprehensive income (loss), before tax		(3,120)	2,223	(15,229)	3,359
Total other comprehensive income (loss), tax		(733)	847	(3,677)	1,271
Total other comprehensive income (loss), net of tax		$ (2,387)	$ 1,376	$ (11,552)	$ 2,088

[1] The pre-tax amounts are included in interest expense on Federal Home Loan Bank 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.