Note 12 - Subsequent Events (Details Textual) - $ / shares		12 Months Ended
	May 03, 2017	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Common Stock, Dividends, Per Share, Declared		$ 4	$ 4	$ 2.06
Subsequent Event [Member]
Common Stock, Dividends, Per Share, Declared	$ 1
Common Stock [Member] | Subsequent Event [Member]
Dividends Payable, Date Declared	May 03, 2017
Dividends Payable, Date to be Paid	May 31, 2017
Dividends Payable, Date of Record	May 15, 2017