Commitments and Contingent Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Commitments to Extend Credit [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Commercial real estate	$ 73,268	$ 128,576
Commercial operating	223,960	236,182
Home equity	38,318	40,896
Other	69,333	70,092
Fair Value Disclosure, Off-balance Sheet Risks, Face Amount, Asset	$ 404,879	475,746
Number of expected days to fund commitments	ninety days
Financial Standby Letter of Credit [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Fair Value Disclosure, Off-balance Sheet Risks, Face Amount, Asset	$ 10,626	$ 9,339
Period when letters of credit expire	one year or less