Fair Value of Plan Assets Held by Asset Category (Detail) (USD $) In Thousands, unless otherwise specified	Aug. 31, 2014		Aug. 31, 2013		Aug. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 136,451		$ 117,478		$ 109,120
Fair value of plan assets allocation	100.00%		100.00%
Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4,642		4,598
Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	119,350		100,766
Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	12,459		12,114
Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4,642		4,598
Fair value of plan assets allocation	3.00%		4.00%
Cash and Cash Equivalents | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4,642		4,598
Equity Securities | Global Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	23,726	[1]	21,637	[1]
Fair value of plan assets allocation	18.00%	[1]	18.00%	[1]
Equity Securities | U.K. Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	22,759	[2]	20,923	[2]
Fair value of plan assets allocation	17.00%	[2]	18.00%	[2]
Equity Securities | Level 2 | Global Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	23,726	[1]	21,637	[1]
Equity Securities | Level 2 | U.K. Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	22,759	[2]	20,923	[2]
Debt Securities | U.K. Corporate Bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	54,595	[3]	43,949	[3]
Fair value of plan assets allocation	40.00%	[3]	38.00%	[3]
Debt Securities | U.K. Government Bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	18,270	[4]	14,257	[4]
Fair value of plan assets allocation	13.00%	[4]	12.00%	[4]
Debt Securities | Level 2 | U.K. Corporate Bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	54,595	[3]	43,949	[3]
Debt Securities | Level 2 | U.K. Government Bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	18,270	[4]	14,257	[4]
Insurance Contracts
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	12,459	[5]	12,114	[5]
Fair value of plan assets allocation	9.00%	[5]	10.00%	[5]
Insurance Contracts | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 12,459	[5]	$ 12,114	[5]

[1] Global equity securities are categorized as Level 2 and include investments that aim to capture global equity market returns by tracking the Financial Times (London) Stock Exchange ("FTSE") AW-World (ex-UK) Index and other similar indexes in Canada.

[2] U.K. equity securities are categorized as Level 2 and include investments in a diversified portfolio that aims to capture the returns of the U.K. equity market. The portfolio tracks the FTSE All-Share Index and invests only in U.K. securities.

[3] U.K. corporate bonds are categorized as Level 2 and include U.K. corporate issued fixed income investments which are managed and tracked to the respective benchmark (AAA-AA-A Bonds-Over 15Y Index).

[4] U.K. government bonds are categorized as Level 2 and include U.K. government-issued fixed income investments which are managed and tracked to the respective benchmark (FTSE U.K. Over 15 Years Gilts Index and FTSE U.K. Over 5 Years Index-Linked).

[5] The assets related to The Netherlands plan consist of an insurance contract that guarantees the payment of the funded pension entitlements, as well as provides a profit share to the Company. The profit share in this contract is not based on actual investments, but, instead on a notional investment portfolio that is expected to return a pre-defined rate. Insurance contract assets are recorded at fair value, which is determined based on the cash surrender value of the insured benefits which is the present value of the guaranteed funded benefits. Insurance contracts are valued using unobservable inputs (Level 3 inputs), primarily by discounting expected future cash flows relating to benefits paid from a notional investment portfolio in order to determine the cash surrender value of the policy. The unobservable inputs consist of estimated future benefits to be paid throughout the duration of the policy and estimated discount rates, which both have an immaterial impact on the fair value estimate of the contract.