Note 7 - Income Taxes - Schedule of Income Tax Provisions (Details) - USD ($)	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Current taxes
Federal, Current taxes	$ 6,034,924	$ 5,754,428	$ 6,608,923
State, Current taxes	138,689	186,822	330,971
Deferred taxes
Federal, Deferred taxes	(25,196)	(55,254)	125,070
State, Deferred taxes	(1,275)	(1,214)	6,356
Income tax provision	$ 6,147,142	$ 5,884,782	$ 7,071,320