Fair Value Measures - Schedule of Assets and Liabilities Measured at Fair Value (Details) - USD ($)	Feb. 29, 2020	Aug. 31, 2019
Fair value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments	$ 610,000	$ 520,000
Total assets measured at fair value	76,031,000	102,042,000
Derivative instruments	1,181,000	3,575,000
Total liabilities measured at fair value	1,181,000	3,575,000
Fair value | Corporate money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	51,537,000	75,849,000
Fair value | Mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds	18,532,000	18,583,000
Fair value | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Certificates of deposit	5,352,000	7,090,000
Level 1 | Fair value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments	0	0
Total assets measured at fair value	51,537,000	75,849,000
Derivative instruments	0	0
Total liabilities measured at fair value	0	0
Level 1 | Fair value | Corporate money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	51,537,000	75,849,000
Level 1 | Fair value | Mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds	0	0
Level 1 | Fair value | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Certificates of deposit	0	0
Level 2 | Fair value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments	610,000	520,000
Total assets measured at fair value	24,494,000	26,193,000
Derivative instruments	1,181,000	3,575,000
Total liabilities measured at fair value	1,181,000	3,575,000
Level 2 | Fair value | Corporate money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Level 2 | Fair value | Mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds	18,532,000	18,583,000
Level 2 | Fair value | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Certificates of deposit	5,352,000	7,090,000
Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	0	0
Level 3 | Fair value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments	0	0
Total assets measured at fair value	0	0
Derivative instruments	0	0
Total liabilities measured at fair value	0	0
Level 3 | Fair value | Corporate money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	0	0
Level 3 | Fair value | Mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds	0	0
Level 3 | Fair value | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Certificates of deposit	$ 0	$ 0