Credit Arrangements (Details Textual) (USD $)	3 Months Ended					3 Months Ended
	Nov. 30, 2011	Nov. 30, 2010	Aug. 31, 2011	Nov. 30, 2011 CMCS [Member]	Nov. 30, 2011 CMCZ [Member]	Nov. 30, 2011 5.625% notes due November 2013 [Member]	Nov. 30, 2011 6.50% notes due July 2017 [Member]	Nov. 30, 2011 7.35% notes due August 2018 [Member]	Nov. 24, 2012 Revolving credit facility [Member]	Dec. 27, 2011 Revolving credit facility [Member]	Nov. 30, 2011 CMCZ short-term credit facilities [Member]
Debt Instrument [Line Items]
Interest rate of notes due						5.625%	6.50%	7.35%
Termination date of interest rate swap						Nov. 15, 2013	Jul. 15, 2017	Aug. 15, 2018
Basis of interest rate swap transaction cost						3.03%	3.74%	3.67%
Revolving credit facility										$ 300,000,000
Revolving credit facility, maximum borrowing capacity									400,000,000	400,000,000	76,000,000
Notional amount of interest rate swap transactions	800,000,000						300,000,000	300,000,000
Amounts outstanding under revolving credit facility									0		42,300,000
Accrued expenses and other payables	374,078,000		377,774,000	17,300,000
Weighted average interest rate					5.50%	3.80%	5.00%	5.60%
Minimum interest coverage ratio for rolling twelve month cumulative period	250.00%
Actual interest coverage ratio	327.00%
Maximum Debt to capitalization ratio	60.00%
Actual Debt to capitalization ratio	53.00%
Interest capitalized in the cost of property, plant and equipment	400,000	200,000
Interest paid	$ 4,400,000	$ 5,000,000