Note 10 - Stockholders' Equity - Cash Dividends Declared (Details) - $ / shares						3 Months Ended		9 Months Ended
	Apr. 22, 2022	Jan. 21, 2022	Oct. 20, 2021	Apr. 23, 2021	Jan. 15, 2021	May 31, 2022	May 31, 2021	May 31, 2022	May 31, 2021
Amount (in dollars per share)	$ 0.07	$ 0.07	$ 0.07	$ 0.065	$ 0.065	$ 0.07	$ 0.065	$ 0.21	$ 0.13
Record date	May 04, 2022	Feb. 02, 2022	Nov. 03, 2021	May 05, 2021	Feb. 03, 2021
Payable date	May 18, 2022	Feb. 16, 2022	Nov. 17, 2021	May 19, 2021	Feb. 17, 2021