Note 4 - Earnings Per Common Share (Details Textual) - shares	3 Months Ended			9 Months Ended
	Mar. 31, 2017	Mar. 31, 2016		Mar. 31, 2017		Mar. 31, 2016
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount		1,032,250		1,683,883		1,391,300
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	0	620,000	[1]	535,000	[1]	576,000	[1]

[1] Calculated using the "Treasury Stock" method as if dilutive securities were exercised and the funds were used to purchase common shares at the average market price during the period.