Note 5 - Share Repurchase Program and Subsequent Event (Details Textual) shares in Thousands, $ in Millions		3 Months Ended	12 Months Ended
	Aug. 13, 2020	Mar. 31, 2022 USD ($) shares	Dec. 31, 2021 shares	May 03, 2022 USD ($) shares	Aug. 31, 2020 shares	Aug. 31, 2019 USD ($) shares
Stock Repurchase Program, Authorized Amount | $						$ 34.0
Stock Repurchase Program, Number of Shares Authorized to be Repurchased (in shares) | shares					2,700	1,800
Stock Repurchased and Retired During Period, Shares (in shares) | shares		1,300	0
Stock Repurchased and Retired During Period, Value | $		$ 25.0
Stock Repurchase Program, Remaining Authorized Repurchase Amount | $		$ 8.4
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased (in shares) | shares		1,300
Subsequent Event [Member]
Stock Repurchase Program, Authorized Amount | $				$ 50.0
Stock Repurchase Program, Number of Shares Authorized to be Repurchased (in shares) | shares				3,100
Stock Split To [Member]
Stockholders' Equity Note, Stock Split, Conversion Ratio	3
Stock Split from [Member]
Stockholders' Equity Note, Stock Split, Conversion Ratio	2