Note 7 - Commitments and Contingencies - Commitments and Contingent Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Commitments	$ 269,554	$ 235,868
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
AHEAD Grants [Member]
Commitments	50	100
Commitments to Extend Credit [Member]
Commitments	$ 261,925	$ 223,882