Accumulated Other Comprehensive (Loss) Income - Components of Accumulated Other Comprehensive (Loss) Income, Net of Taxes (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Beginning balance	$ (14,462)	$ (9,955)
Net Change	1,300	1,753
Ending balance	(13,162)	(8,202)
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	1,711	(1,472)
Net Change	1,344	1,695
Ending balance	3,055	223
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	(157)	0
Net Change	(219)	0
Ending balance	(376)	0
Net Change Related to Defined Benefit Pension Plan [Member]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract]
Beginning balance	(16,016)	(8,483)
Net Change	175	58
Ending balance	$ (15,841)	$ (8,425)