Note 18 - California First National Bancorp (Parent Only) Financial Information: (Detail) - Condensed Balance Sheets of California First National Bancorp: (Parentheticals) (USD $)	Jun. 30, 2012	Jun. 30, 2011
Preferred stock, shares authorized	2,500,000	2,500,000
Preferred stock, shares issued	0	0
Common stock, par value (in Dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	20,000,000	20,000,000
Common stock, shares issued	10,433,684	10,417,597
Common stock, shares outstanding	10,433,684	10,417,597
Parent Company [Member]
Preferred stock, shares authorized	2,500,000,000	2,500,000,000
Preferred stock, shares issued	0	0
Common stock, par value (in Dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	20,000,000,000	20,000,000,000
Common stock, shares issued	10,433,684,000	10,417,597,000
Common stock, shares outstanding	10,433,684,000	10,417,597,000