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, 2016
Aug. 31, 2015
Schedule of Pension Plan Assets by Fair Value [Line Items]    
Defined Benefit Plan, Fair Value of Plan Assets $ 39,489 $ 39,181
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, Fair Value of Plan Assets $ 347 $ 314
Percentage of fair value of pension plan assets 0.90% 0.80%
Fixed Income Securities | Fair Value, Inputs, Level 2    
Schedule of Pension Plan Assets by Fair Value [Line Items]    
Defined Benefit Plan, Fair Value of Plan Assets $ 11,723 $ 12,581
Percentage of fair value of pension plan assets 29.70% 32.10%
Fixed Income Securities | Corporate Bond Securities | Fair Value, Inputs, Level 2    
Schedule of Pension Plan Assets by Fair Value [Line Items]    
Defined Benefit Plan, Fair Value of Plan Assets $ 8,372 $ 9,481
Percentage of fair value of pension plan assets 21.20% 24.20%
Fixed Income Securities | Mutual Funds | Fair Value, Inputs, Level 2    
Schedule of Pension Plan Assets by Fair Value [Line Items]    
Defined Benefit Plan, Fair Value of Plan Assets $ 3,351 $ 3,100
Percentage of fair value of pension plan assets 8.50% 7.90%
Equity Securities | Mutual Funds | Fair Value, Inputs, Level 1    
Schedule of Pension Plan Assets by Fair Value [Line Items]    
Defined Benefit Plan, Fair Value of Plan Assets $ 27,419 $ 26,286
Percentage of fair value of pension plan assets 69.40% 67.10%