Note 6 - 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	Feb. 28, 2019	Aug. 31, 2018
Prepaid Expenses and Other Current Assets [Member]
Derivative assets	$ 533	$ 90
Other Assets [Member]
Derivative assets	147
Accounts Payable and Accrued Liabilities [Member]
Derivative liabilities	2,044	1,731
Deferred Rent and Other Noncurrent Liabilities [Member]
Derivative liabilities	$ 249	$ 2,305