Note 5 - Derivative Instruments - Fair Value Amounts of Derivative Instruments and Gains (Details) - Foreign Exchange Contract [Member] - Cash Flow Hedging [Member] - Designated as Hedging Instrument [Member] - USD ($) $ in Thousands	Aug. 31, 2018	Aug. 31, 2017
Prepaid Expenses and Other Current Assets [Member]
Derivative assets	$ 90	$ 3,796
Other Assets [Member]
Derivative assets		2,346
Accounts Payable and Accrued Liabilities [Member]
Derivative liabilities	1,731
Deferred Rent and Other Noncurrent Liabilities [Member]
Derivative liabilities	$ 2,305