Debentures (Details) $ / shares in Units, shares in Thousands	3 Months Ended		9 Months Ended
	May 31, 2024 USD ($) $ / shares shares	May 31, 2023 USD ($)	Nov. 30, 2023	Feb. 29, 2024 USD ($)	Nov. 13, 2023 USD ($)
Debt Instrument [Line Items]
Redemption period, end date	Feb. 15, 2029
Par value of convertible debentures	$ 1,000
Interest expense, debt	2,000,000	$ 2,000,000
Long-term notes (note 5)	194,000,000			$ 194,000,000
Related Party Principal Amounts of 2020 Debenture Owned	330,000,000
2020 Debentures
Debt Instrument [Line Items]
Face amount of debt					$ 365,000,000
Redemption period, end date			Nov. 13, 2023
Senior Convertible Notes
Debt Instrument [Line Items]
Face amount of debt	200,000,000			$ 194,000,000
Amortization of Debt Issuance Costs	0
Long-Term Debt	$ 194,000,000
Interest rate	3.00%
Debt Instrument, Convertible, Number of Equity Instruments - with decimals	257.5826
Conversion of stock (in shares) | shares	52,000
Conversion price (in dollars per share) | $ / shares	$ 3.88
Date of first interest payment	Aug. 15, 2024
Debt Instrument, Interest Rate Terms	The Notes will bear interest at a rate of 3.00% per annum, payable semi-annually in arrears on February 15 and August 15 of each year, beginning on August 15, 2024
Payments of Debt Issuance Costs	$ 6,000,000