Note 15 - Regulatory Capital Requirements (Details) - Capital and Capital Ratio Information - USD ($) $ in Thousands	Jun. 30, 2015	Jun. 30, 2014
California First National Bancorp [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common equity Tier 1 capital	$ 187,987	$ 183,321
Common equity Tier 1 capital, ratio	29.17%	31.84%
Tier 1 risk-based capital	$ 187,987	$ 183,321
Tier 1 risk-based capital, ratio	29.17%	31.84%
Total risk-based capital	$ 194,493	$ 188,645
Total risk-based capital, ratio	30.18%	32.76%
Tier 1 leverage capital	$ 187,987	$ 183,321
Tier 1 leverage capital, ratio	26.79%	32.80%
California First National Bank [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common equity Tier 1 capital	$ 109,147	$ 102,780
Common equity Tier 1 capital, ratio	17.65%	19.61%
Tier 1 risk-based capital	$ 109,147	$ 102,780
Tier 1 risk-based capital, ratio	17.65%	19.61%
Total risk-based capital	$ 115,306	$ 107,639
Total risk-based capital, ratio	18.65%	20.54%
Tier 1 leverage capital	$ 109,147	$ 102,780
Tier 1 leverage capital, ratio	17.10%	21.09%