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, 2019
Aug. 31, 2018
Schedule of Pension Plan Assets by Fair Value [Line Items]    
Defined Benefit Plan, Plan Assets, Amount $ 40,412 $ 40,244
Percentage of fair value of pension plan assets 100.00% 100.00%
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 $ 304 $ 559
Percentage of fair value of pension plan assets 0.80% 1.40%
Fixed Income Securities | Fair Value, Inputs, Level 2    
Schedule of Pension Plan Assets by Fair Value [Line Items]    
Defined Benefit Plan, Plan Assets, Amount $ 28,333 $ 19,921
Percentage of fair value of pension plan assets 70.10% 49.50%
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 $ 5,127 $ 19,107
Percentage of fair value of pension plan assets 12.70% 47.50%
Fixed Income Securities | Mutual Funds | Fair Value, Inputs, Level 2    
Schedule of Pension Plan Assets by Fair Value [Line Items]    
Defined Benefit Plan, Plan Assets, Amount $ 23,206 $ 814
Percentage of fair value of pension plan assets 57.40% 2.00%
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 $ 11,775 $ 19,764
Percentage of fair value of pension plan assets 29.10% 49.10%