U.S. Pension Plan Investment Allocations by Asset Category (Detail) (USD $) In Thousands, unless otherwise specified	Aug. 31, 2013	Aug. 31, 2012
Schedule of Pension Plan Assets by Fair Value [Line Items]
Fair value of pension plan assets	$ 34,054	$ 33,695
Percentage of fair value of pension plan assets	100.00%	100.00%
Cash and cash equivalents | Level 1 Valuation
Schedule of Pension Plan Assets by Fair Value [Line Items]
Fair value of pension plan assets	348	250
Percentage of fair value of pension plan assets	1.00%	0.70%
Fixed Income Securities | Level 2 Valuation
Schedule of Pension Plan Assets by Fair Value [Line Items]
Fair value of pension plan assets	12,205	10,477
Percentage of fair value of pension plan assets	35.90%	31.10%
Fixed Income Securities | Government Bonds | Level 2 Valuation
Schedule of Pension Plan Assets by Fair Value [Line Items]
Fair value of pension plan assets	0	310
Percentage of fair value of pension plan assets	0.00%	0.90%
Fixed Income Securities | Corporate Bond | Level 2 Valuation
Schedule of Pension Plan Assets by Fair Value [Line Items]
Fair value of pension plan assets	8,741	7,489
Percentage of fair value of pension plan assets	25.70%	22.20%
Fixed Income Securities | Mutual Funds | Level 2 Valuation
Schedule of Pension Plan Assets by Fair Value [Line Items]
Fair value of pension plan assets	3,464	2,678
Percentage of fair value of pension plan assets	10.20%	8.00%
Equity Securities | Mutual Funds | Level 1 Valuation
Schedule of Pension Plan Assets by Fair Value [Line Items]
Fair value of pension plan assets	$ 21,501	$ 22,968
Percentage of fair value of pension plan assets	63.10%	68.20%