Note 15 - Capital and Capital Ratio Information (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Jun. 30, 2015
California First National Bancorp [Member]
Common equity Tier 1 capital	$ 189,677	$ 187,987
Common equity Tier 1 capital, ratio	25.12%	29.17%
Tier 1 risk-based capital	$ 189,677	$ 187,987
Tier 1 risk-based capital, ratio	25.12%	29.17%
Total risk-based capital	$ 196,589	$ 194,493
Total risk-based capital, ratio	26.04%	30.18%
Tier 1 leverage capital	$ 189,677	$ 187,987
Tier 1 leverage capital, ratio	21.67%	26.79%
California First National Bank [Member]
Common equity Tier 1 capital	$ 116,379	$ 109,147
Common equity Tier 1 capital, ratio	15.88%	17.65%
Tier 1 risk-based capital	$ 116,379	$ 109,147
Tier 1 risk-based capital, ratio	15.88%	17.65%
Total risk-based capital	$ 123,091	$ 115,306
Total risk-based capital, ratio	16.79%	18.65%
Tier 1 leverage capital	$ 116,379	$ 109,147
Tier 1 leverage capital, ratio	13.94%	17.10%