Annual report pursuant to Section 13 and 15(d)

U.S. Pension Plan Investment Allocations by Asset Category (Detail)

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U.S. Pension Plan Investment Allocations by Asset Category (Detail) - USD ($)
$ in Thousands
Aug. 31, 2020
Aug. 31, 2019
Schedule of Pension Plan Assets by Fair Value [Line Items]    
Defined Benefit Plan, Plan Assets, Amount $ 39,935 $ 40,412
Percentage of fair value of pension plan assets 100.00% 100.00%
Fixed Income Securities    
Schedule of Pension Plan Assets by Fair Value [Line Items]    
Percentage of fair value of pension plan assets 70.90% 70.10%
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount $ 28,297 $ 28,333
Fixed Income Securities | Corporate Bond Securities | Fair Value, Inputs, Level 2    
Schedule of Pension Plan Assets by Fair Value [Line Items]    
Defined Benefit Plan, Plan Assets, Amount $ 0 $ 5,127
Percentage of fair value of pension plan assets 0.00% 12.70%
Fixed Income Securities | Mutual Funds | Fair Value, Inputs, Level 1    
Schedule of Pension Plan Assets by Fair Value [Line Items]    
Defined Benefit Plan, Plan Assets, Amount $ 23,091 $ 23,206
Percentage of fair value of pension plan assets 57.90% 57.40%
Fixed Income Securities | US Treasury Securities | Fair Value, Inputs, Level 2    
Schedule of Pension Plan Assets by Fair Value [Line Items]    
Defined Benefit Plan, Plan Assets, Amount $ 5,206 $ 0
Percentage of fair value of pension plan assets 13.00% 0.00%
Cash and cash equivalents | Fair Value, Inputs, Level 1    
Schedule of Pension Plan Assets by Fair Value [Line Items]    
Defined Benefit Plan, Plan Assets, Amount $ 0 $ 304
Percentage of fair value of pension plan assets 0.00% 0.80%
Equity Securities | Mutual Funds | Fair Value, Inputs, Level 1    
Schedule of Pension Plan Assets by Fair Value [Line Items]    
Defined Benefit Plan, Plan Assets, Amount $ 11,583 $ 11,775
Percentage of fair value of pension plan assets 29.00% 29.10%
Income Receivable    
Schedule of Pension Plan Assets by Fair Value [Line Items]    
Defined Benefit Plan, Plan Assets, Amount   $ 0
Percentage of fair value of pension plan assets 0.10% 0.00%
Defined Benefit Plan, Plan Assets, Investment within Plan Asset Category, Amount $ 55