Note 5 - Derivative Instruments - Derivatives in Cash Flow Hedging Relationships (Details) - Cash Flow Hedging [Member] - Designated as Hedging Instrument [Member] - Foreign Exchange Contract [Member] - Selling, General and Administrative Expenses [Member] - USD ($) $ in Thousands	12 Months Ended
	Aug. 31, 2018	Aug. 31, 2017	Aug. 31, 2016
Foreign currency forward contracts	$ (7,700)	$ 5,183	$ (1,806)
Foreign currency forward contracts	$ 3,106	$ (2,883)	$ (451)