Note 19 - Commitments and Contingencies (Details Textual) $ in Thousands	12 Months Ended
	Aug. 31, 2018 USD ($) ft²	Aug. 31, 2017 USD ($)	Aug. 31, 2016 USD ($)	Feb. 14, 2018 ft²
Operating Leases, Rent Expense, Total	$ 54,600	$ 48,400	$ 43,200
Other Liabilities, Noncurrent, Total	38,989	37,188
Letters of Credit Outstanding, Amount	2,000
Purchase Commitment, Remaining Minimum Amount Committed	79,000	81,000
Deferred Rent [Member]
Other Liabilities, Total	39,400	37,400
Other Liabilities, Noncurrent, Total	$ 33,600	$ 33,500
Non-cancelable Operating Lease [Member]
Area of Real Estate Property | ft²	1,750,000
Norwalk Connecticut [Member]
Area of Real Estate Property | ft²	202,000			173,000