Other Comprehensive Income (Loss) (Components of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Accumulated other comprehensive income (loss), beginning balance	$ (23,510)	$ (19,757)
Other comprehensive income (loss) before reclassifications	(9,702)	413
Amounts reclassed from accumulated other comprehensive income (loss)	537	299
Total other comprehensive income (loss), net of tax	(9,165)	712
Accumulated other comprehensive income (loss), ending balance	(32,675)	(19,045)
Net Unrealized Gains (Losses) on AFS Securities [Member]
Accumulated other comprehensive income (loss), beginning balance	(7,534)	(6,825)
Other comprehensive income (loss) before reclassifications	(10,414)	401
Amounts reclassed from accumulated other comprehensive income (loss)	0	0
Total other comprehensive income (loss), net of tax	(10,414)	401
Accumulated other comprehensive income (loss), ending balance	(17,948)	(6,424)
Net Unrealized Losses on Cash Flow Hedges [Member]
Accumulated other comprehensive income (loss), beginning balance	(428)	(300)
Other comprehensive income (loss) before reclassifications	712	12
Amounts reclassed from accumulated other comprehensive income (loss)	177	86
Total other comprehensive income (loss), net of tax	889	98
Accumulated other comprehensive income (loss), ending balance	461	(202)
Pension Benefit Adjustment [Member]
Accumulated other comprehensive income (loss), beginning balance	(15,548)	(12,632)
Other comprehensive income (loss) before reclassifications	0	0
Amounts reclassed from accumulated other comprehensive income (loss)	360	213
Total other comprehensive income (loss), net of tax	360	213
Accumulated other comprehensive income (loss), ending balance	$ (15,188)	$ (12,419)