Note 14 - Commitments and Contingent Liabilities (Details Textual) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Loss Contingency Accrual, Ending Balance	$ 350
Standby Letters of Credit [Member]
Fair Value Disclosure, Off-balance Sheet Risks, Amount, Liability	$ 18,900	$ 14,800
Standby Letters of Credit [Member] | Minimum [Member]
Guarantee Obligations, Agreement Term	1 year
Standby Letters of Credit [Member] | Maximum [Member]
Guarantee Obligations, Agreement Term	2 years
Commitments to Extend Credit and Standby Letters of Credit [Member]
Fair Value Disclosure, Off-balance Sheet Risks, Amount, Liability	$ 692,400	$ 688,300