Note I - Stockholders' Equity - Schedule of Stockholders' Equity (Details) (Parentheticals) - $ / shares	3 Months Ended				6 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Sep. 30, 2018	Jun. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Cash dividends, per share (in dollars per share)	$ 0.02		$ 0.06		$ 0.06	$ 0.09
Retained Earnings [Member]
Cash dividends, per share (in dollars per share)	$ 0.02	$ 0.04	$ 0.06	$ 0.03