Note 6 - Changes in Shareholders' Equity and Comprehensive Income: (Details Textual) - USD ($) $ in Millions	6 Months Ended
Sep. 30, 2019	Sep. 30, 2018
Stock Repurchased and Retired During Period, Shares	613,000	0
Stock Repurchased and Retired During Period, Value	$ 11.5
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 28.7

Equity impact of the value of stock that has been repurchased and retired during the period. The excess of the purchase price over par value can be charged against retained earnings (once the excess is fully allocated to additional paid in capital).

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