Accumulated Other Comprehensive (Loss) Income - Components of Accumulated Other Comprehensive (Loss) Income, Net of Taxes (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Beginning balance	$ (19,454)	$ (16,708)
Net Change	462	1,227
Ending balance	(18,992)	(15,481)
Net Unrealized Holding (Losses) Gains on Available-for-Sale Investment Securities [Member]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Beginning balance	(4,988)	(592)
Net Change	263	1,413
Ending balance	(4,725)	821
Net Change Related to Derivative Used for Cash Flow Hedge [Member]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Beginning balance	(141)	(285)
Net Change	51	(354)
Ending balance	(90)	(639)
Net Change Related to Defined Benefit Pension Plan [Member]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Beginning balance	(14,325)	(15,831)
Net Change	148	168
Ending balance	$ (14,177)	$ (15,663)