Note 15 - Commitments and Contingencies - Commitments and Contingent Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Commitments	$ 227,744	$ 229,387
Standby Letters of Credit [Member]
Commitments	6,692	1,967
Federal Home Loan Bank of San Francisco Affordable Housing Grant Sponsorships [Member]
Commitments	3,338	3,338
Commitments to Extend Credit [Member]
Commitments	$ 217,714	$ 224,082