Income Taxes (Schedule of Deferred Tax Assets and Deferred Tax Liabilities) (Details) (USD $)
In Thousands, unless otherwise specified
 12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Asset    
Allowance for possible losses on loans 7,397 $ 7,564
Pension and other benefits 4,018 3,900
Net unrealized losses on derivative instruments 3,200 1,369
Net unrealized losses on postretirement plans 1,165 992
Deferred compensation and benefits 945 963
Purchase accounting and deposit premium 329 321
Net unrealized losses on AFS securities 172 4,288
Allowance for OREO valuation 107 59
Allowance for OTTI of investments 71 71
Other 1,313 695
Total 18,717 20,222
Liability    
Depreciation 1,910 1,765
Deferred loan origination fees 1,581 1,390
Prepaid expenses 620 766
MSRs 172 254
Total 4,283 $ 4,175
Minimum [Member]    
Income Tax Contingency [Line Items]    
Open tax years 2011  
Maximum [Member]    
Income Tax Contingency [Line Items]    
Open tax years 2013