Note 18 - California First National Bancorp (Parent Only) Financial Information (Details) - Condensed Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2012
ASSETS
Cash and cash equivalents	$ 60,240	$ 40,122	$ 75,469	$ 56,921
Other assets	791	771
	731,074	579,550	558,903
Liabilities
Accrued liabilities	2,278	2,553
	$ 542,856	$ 395,805
Stockholders' equity
Preferred stock; 2,500,000 shares authorized; none issued
Common stock, $.01 par value; 20,000,000 shares authorized; 10,459,924 (2015) and 10,459,924 (2014) issued and outstanding	$ 105	$ 105
Retained earnings	184,506	179,844
Other comprehensive income, net of tax	231	424
	188,218	183,745	180,879	196,439
	731,074	579,550
Parent Company [Member]
ASSETS
Cash and cash equivalents	3,091	2,796	$ 4,584	$ 6,247
Intercompany receivable	69	32
Intercompany note receivable		0
Other assets	664	1,170
Premises and other fixed assets	197	261
	189,109	184,596
Liabilities
Accrued liabilities	492	495
Intercompany payable	120	126
Income taxes payable- deferred	279	230
	891	851
Stockholders' equity
Preferred stock; 2,500,000 shares authorized; none issued	0	0
Common stock, $.01 par value; 20,000,000 shares authorized; 10,459,924 (2015) and 10,459,924 (2014) issued and outstanding	105	105
Additional paid in capital	3,376	3,372
Retained earnings	184,506	179,844
Other comprehensive income, net of tax	231	424
	188,218	183,745
	189,109	184,596
Investments in Banking Subsidiary [Member] | Parent Company [Member]
ASSETS
Investment in subsidiary	109,382	103,000
Investments in Non-banking Subsidiary [Member] | Parent Company [Member]
ASSETS
Investment in subsidiary	$ 75,706	$ 77,337