Commitments and Contingent Liabilities (Details) $ in Millions	3 Months Ended
	Mar. 31, 2018 USD ($)
Line of Credit Facility [Line Items]
Commitments to extend credit	$ 256.2
Standby letters of credit	$ 3.1
Standby Letters of Credit [Member]
Line of Credit Facility [Line Items]
Standby letter of credit term, or less	2 years