Note 4 - Fair Value Measures - Assets and Liabilities Measured at Fair Value (Details) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands		Feb. 28, 2018	Aug. 31, 2017
Derivative instruments	[1]	$ 3,921	$ 6,142
Total assets measured at fair value		70,951	65,263
Derivative instruments	[1]
Total liabilities measured at fair value
Money Market Funds [Member]
Corporate money market funds	[2]	35,472	26,677
Mutual Funds [Member]
Mutual funds	[3]	20,243	18,364
Certificates of Deposit [Member]
Certificates of deposit	[4]	11,315	14,080
Fair Value, Inputs, Level 1 [Member]
Derivative instruments	[1]
Total assets measured at fair value		35,472	26,677
Derivative instruments	[1]
Total liabilities measured at fair value
Fair Value, Inputs, Level 1 [Member] | Money Market Funds [Member]
Corporate money market funds	[2]	35,472	26,677
Fair Value, Inputs, Level 1 [Member] | Mutual Funds [Member]
Mutual funds	[3]
Fair Value, Inputs, Level 1 [Member] | Certificates of Deposit [Member]
Certificates of deposit	[4]
Fair Value, Inputs, Level 2 [Member]
Derivative instruments	[1]	3,921	6,142
Total assets measured at fair value		35,479	38,586
Derivative instruments	[1]
Total liabilities measured at fair value
Fair Value, Inputs, Level 2 [Member] | Money Market Funds [Member]
Corporate money market funds	[2]
Fair Value, Inputs, Level 2 [Member] | Mutual Funds [Member]
Mutual funds	[3]	20,243	18,364
Fair Value, Inputs, Level 2 [Member] | Certificates of Deposit [Member]
Certificates of deposit	[4]	11,315	14,080
Fair Value, Inputs, Level 3 [Member]
Derivative instruments	[1]
Total assets measured at fair value
Derivative instruments	[1]
Total liabilities measured at fair value
Fair Value, Inputs, Level 3 [Member] | Money Market Funds [Member]
Corporate money market funds	[2]
Fair Value, Inputs, Level 3 [Member] | Mutual Funds [Member]
Mutual funds	[3]
Fair Value, Inputs, Level 3 [Member] | Certificates of Deposit [Member]
Certificates of deposit	[4]

[1] The Company utilizes the income approach to measure fair value for its derivative instruments (foreign currency forward contracts). The income approach uses pricing models that rely on market observable inputs such as spot, forward and interest rates, as well as credit default swap spreads and therefore, are classified as Level 2.

[2] The Company's corporate money market funds are traded in an active market and the net asset value of each fund on the last day of the quarter is used to determine its fair value. As such, the Company's corporate money market funds are classified as Level 1 and included in cash and cash equivalents on the Consolidated Balance Sheets.

[3] The Company's mutual funds have a fair value based on the fair value of the underlying investments held by the mutual funds allocated to each share of the mutual fund using a net asset value approach. The fair value of the underlying investments is based on observable inputs. As such, the Company's mutual funds are classified as Level 2 and are classified as investments (short-term) on the Consolidated Balance Sheets.

[4] The Company's certificates of deposit held for investment are not debt securities and are classified as Level 2. These certificates of deposit have original maturities greater than three months, but less than one year and, as such, are classified as investments (short-term) on the Consolidated Balance Sheets.