Note 1 - Basic and Diluted Net Income Per Share (Details) - USD ($)	3 Months Ended								12 Months Ended
	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2014
Net earnings	$ 3,755,000	$ 1,611,000	$ 1,558,000	$ 1,724,000	$ 1,360,000	$ 1,678,000	$ 3,557,000	$ 2,459,000	$ 8,648,000	$ 9,055,000	$ 7,051,000
Weighted average number of common shares outstanding assuming no exercise of outstanding options (in shares)									10,399,393	10,459,924	10,453,107
Dilutive stock options using the treasury stock method (in shares)											3,252
Dilutive common shares outstanding (in shares)									10,399,393	10,459,924	10,456,359
Basic earnings per common share (in dollars per share)	$ 0.37	$ 0.15	$ 0.15	$ 0.16	$ 0.13	$ 0.16	$ 0.34	$ 0.24	$ 0.83	$ 0.87	$ 0.67
Diluted earnings per common share (in dollars per share)	$ 0.37	$ 0.15	$ 0.15	$ 0.16	$ 0.13	$ 0.16	$ 0.34	$ 0.24	$ 0.83	$ 0.87	$ 0.67