Accumulated Other Comprehensive (Loss) Income - Components of Accumulated Other Comprehensive (Loss) Income, Net of Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Beginning balance			$ (19,454)	$ (16,708)
Net Change	$ 1,810	$ 1,111	2,272	2,338
Ending balance	(17,182)	(14,370)	(17,182)	(14,370)
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			1,961	2,499
Ending balance	(3,027)	1,907	(3,027)	1,907
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			14	(497)
Ending balance	(127)	(782)	(127)	(782)
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			297	336
Ending balance	$ (14,028)	$ (15,495)	$ (14,028)	$ (15,495)