Note 18 - California First National Bancorp (Parent Only) Financial Information (Details) - Condensed Statements of Earnings - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2013
Non-interest Expenses:
Salaries & benefits									$ 8,582	$ 7,796	$ 8,505
Occupancy									634	682	922
Professional services									664	590	585
Income (loss) before taxes and equity in undistributed earnings of subsidiaries									14,815	11,073	11,685
Income tax expense									5,760	4,022	4,331
Net Income	$ 1,360	$ 1,678	$ 3,557	$ 2,459	$ 1,846	$ 1,190	$ 2,184	$ 1,831	9,055	7,051	7,354
Parent Company [Member]
Income:
Dividends from non-bank subsidiary									5,000	0	0
Interest income non-bank subsidiaries									0	22	331
Other interest income									1	1	5
									5,828	743	1,300
Non-interest Expenses:
Salaries & benefits									1,209	1,186	1,332
Occupancy									95	140	142
Professional services									244	274	282
Other general & administrative									322	488	171
									1,870	2,088	1,927
Income (loss) before taxes and equity in undistributed earnings of subsidiaries									3,958	(1,345)	(627)
Income tax expense									(154)	(498)	(204)
Equity in undistributed earnings of subsidiaries									4,943	7,898	7,777
Net Income									9,055	7,051	7,354
Investments in Banking Subsidiary [Member] | Parent Company [Member]
Income:
Management fee income from subsidiary									676	569	336
Investments in Non-banking Subsidiary [Member] | Parent Company [Member]
Income:
Management fee income from subsidiary									$ 151	$ 151	$ 628