Note 18 - Commitments and Contingencies (Details Textual) $ in Thousands	3 Months Ended		9 Months Ended
	May 31, 2017 USD ($) ft² a	May 31, 2016 USD ($)	May 31, 2017 USD ($) ft² a	May 31, 2016 USD ($)	Aug. 31, 2016 USD ($)
Operating Leases, Rent Expense	$ 12,400	$ 11,100	$ 35,300	$ 32,000
Other Liabilities, Noncurrent	37,035		37,035		$ 33,080
Letters of Credit Outstanding, Amount	$ 1,900		$ 1,900
Purchase Commitment, Remaining Minimum Amount Committed					67,500
Largest Individual Client Percent Of Total Subscriptions	2.00%		2.00%
Percentage of Subscription from Ten Largest Clients	15.00%		15.00%
Allowance for Doubtful Accounts Receivable	$ 1,700		$ 1,700		1,500
Deferred Rent [Member]
Other Liabilities	37,200		37,200		34,400
Other Liabilities, Noncurrent	$ 33,900		$ 33,900		$ 31,200
Norwalk Connecticut [Member]
Area of Real Estate Property | ft²	202,000		202,000
Non-cancelable Operating Lease [Member]
Area of Real Estate Property | a	1,226,000		1,226,000
Increase (Decrease) in Area of Real Estate Property | a	154,000		154,000
Increase (Decrease) in Area of Real Estate Property, Percent			14.40%