Income Taxes Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deferred Tax Assets, Gross [Abstract]
Allowance for Loan Losses	$ 6,609	$ 6,453
Pension and Deferred Compensation Plans	3,961	3,973
Pension Liability Included in Accumulated Other Comprehensive Income	4,023	5,550
Other	502	557
Deferred Tax Assets, Unrealized Losses on Trading Securities	239	0
Total Gross Deferred Tax Assets	15,334	16,533
Valuation Allowance for Deferred Tax Assets	0	0
Total Gross Deferred Tax Assets, Net of Valuation Allowance	15,334	16,533
Deferred Tax Liabilities, Gross [Abstract]
Pension Plans	8,399	8,680
Depreciation	1,430	1,383
Deferred Income	4,199	4,167
Net Unrealized Gains on Securities Available-for-Sale Included in Accumulated Other Comprehensive Income	0	405
Goodwill	5,324	5,316
Total Gross Deferred Tax Liabilites	$ 19,352	$ 19,951