Note 7 - Changes in Shareholders' Equity (Details Textual) - USD ($) shares in Thousands, $ in Millions	3 Months Ended
Jun. 30, 2022	Jun. 30, 2021
Stock Repurchased and Retired During Period, Shares (in shares)	0	0
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 28.7

Number of shares that have been repurchased and retired during the period.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration