Note 8 - Commitments and Contingent Liabilities - Unused and Available Credit Balances of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Financial instruments	$ 164,825	$ 138,523
Financial Standby Letter of Credit [Member]
Financial instruments	42,564	36,657
Performance Guarantee [Member]
Financial instruments	1,962	2,471
Construction Mortgages [Member]
Financial instruments	28,968	21,363
Personal Line Of Credit [Member]
Financial instruments	6,138	5,905
Overdraft Protection Lines [Member]
Financial instruments	5,692	5,680
Home Equity Lines of Credit [Member]
Financial instruments	15,205	14,722
Commercial Lines Of Credit [Member]
Financial instruments	$ 64,296	$ 51,725