Note 7 - Commitments and Contingencies - Commitments and Contingent Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Commitments	$ 276,316	$ 275,102
Standby Letters of Credit [Member]
Commitments	4,537	4,406
Federal Home Loan Bank of San Francisco Affordable Housing Grant Sponsorships [Member]
Commitments	3,338	3,338
AHEAD Grants [Member]
Commitments	110	110
Commitments to Extend Credit [Member]
Commitments	$ 268,331	$ 267,248