Note 2 - Income Taxes (Details Textual) - USD ($)	3 Months Ended		6 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent			34.00%
Income Tax Expense (Benefit)	$ 1,701,000	$ 766,200	$ 1,368,000	$ 804,200
Effective Income Tax Rate Reconciliation, Percent				30.00%