Fair Value Measures - Schedule of Assets and Liabilities Measured at Fair Value (Details) - USD ($)	Feb. 28, 2021	Aug. 31, 2020
Fair value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments	$ 3,169,000	$ 3,644,000
Total assets measured at fair value	272,795,000	300,068,000
Derivative instruments	3,711,000	5,773,000
Total liabilities measured at fair value	3,711,000	5,773,000
Fair value | Corporate money market funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	251,858,000	276,852,000
Fair value | Mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds	17,768,000	17,257,000
Fair value | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Certificates of deposit		2,315,000
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	251,858,000	276,852,000
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	251,858,000	276,852,000
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
Level 2 | Fair value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative instruments	3,169,000	3,644,000
Total assets measured at fair value	20,937,000	23,216,000
Derivative instruments	3,711,000	5,773,000
Total liabilities measured at fair value	3,711,000	5,773,000
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	17,768,000	17,257,000
Level 2 | Fair value | Certificates of deposit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Certificates of deposit		2,315,000
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