Note 7 - Commitments and Contingencies - Commitments and Contingent Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Commitments	$ 263,252	$ 235,768
Standby Letters of Credit [Member]
Commitments	4,241	8,548
Federal Home Loan Bank of San Francisco Affordable Housing Grant Sponsorships [Member]
Commitments	3,338	3,338
Commitments to Extend Credit [Member]
Commitments	$ 255,673	$ 223,882