Derivative Financial Instruments And Hedging Activities (Narrative) (Details) (USD $)	3 Months Ended								3 Months Ended		3 Months Ended
	Aug. 31, 2007	Nov. 30, 2011	Aug. 31, 2011	Feb. 28, 2011	Nov. 30, 2010	Nov. 30, 2011 7.750% Senior Notes Due 2016 [Member]	Aug. 31, 2011 7.750% Senior Notes Due 2016 [Member]	Feb. 28, 2011 7.750% Senior Notes Due 2016 [Member]	Nov. 30, 2011 8.250% Senior Notes Due 2018 [Member]	Aug. 31, 2007 8.250% Senior Notes Due 2018 [Member]	Nov. 30, 2011 Foreign Currency Risk Management Hedging Arrangements [Member]
Derivative [Line Items]
Aggregate notional amount outstanding of foreign currency denominated revenues and expenses designated as cash flow hedges		$ 255,700,000			$ 43,500,000
Aggregate notional amount outstanding of forward contracts to hedge transactional exposure		779,500,000			420,000,000
Existing losses related to foreign currency risk management hedging arrangements											1,600,000
Existing losses related to interest rate risk management hedging arrangements		4,000,000
Notional amount of interest rate swaps designated as fair value hedges				200,000,000
Senior unsecured notes, interest rate						7.75%		7.75%	8.25%	8.25%
Fair value adjustment related to interest rate swap including accrued interest on interest rate swaps							12,200,000
Hedge accounting adjustment recorded		10,977,000	11,570,000
Accrued interest on interest rate swaps							600,000
Notional amount of interest rate swaps designated as cash flow hedges	400,000,000
Payment to settle interest rate swaps	$ 43,100,000
Expiry date									Mar. 15, 2018