Credit Arrangements (Narrative) (Details) (USD $)	3 Months Ended		6 Months Ended
	Feb. 29, 2012	Feb. 28, 2011	Feb. 29, 2012	Feb. 28, 2011	Aug. 31, 2011
Debt Instrument [Line Items]
Outstanding stand-by letter of credit	$ 26,600,000		$ 26,600,000
Notional amount of interest rate swap transactions	800,000,000		800,000,000
Accrued expenses and other payables	329,993,000		329,993,000		377,774,000
Interest capitalized in the cost of property, plant and equipment	0		0
Interest paid	30,200,000	31,600,000	34,600,000	36,600,000
CMCS [Member]
Debt Instrument [Line Items]
Accrued expenses and other payables	14,300,000		14,300,000
CMCZ [Member]
Debt Instrument [Line Items]
Revolving credit facility, maximum borrowing capacity	82,600,000		82,600,000
Amounts outstanding under revolving credit facility	45,100,000		45,100,000
Short-term debt weighted average interest rate	5.20%		5.20%
5.625% Notes Due November 2013 [Member]
Debt Instrument [Line Items]
Interest rate of notes due	5.625%		5.625%
Termination date of interest rate swap			Nov. 15, 2013
Basis of interest rate swap transaction cost	3.03%		3.03%
Weighted average interest rate	3.70%		3.70%
6.50% Notes Due July 2017 [Member]
Debt Instrument [Line Items]
Interest rate of notes due	6.50%		6.50%
Termination date of interest rate swap			Jul. 15, 2017
Basis of interest rate swap transaction cost	3.74%		3.74%
Notional amount of interest rate swap transactions	300,000,000		300,000,000
Weighted average interest rate	4.90%		4.90%
7.35% Notes Due August 2018 [Member]
Debt Instrument [Line Items]
Interest rate of notes due	7.35%		7.35%
Termination date of interest rate swap			Aug. 15, 2018
Basis of interest rate swap transaction cost	3.67%		3.67%
Notional amount of interest rate swap transactions	300,000,000		300,000,000
Weighted average interest rate	5.50%		5.50%
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility expired borrowing capacity	400,000,000		400,000,000
Revolving credit facility	300,000,000		300,000,000
Revolving credit facility, maximum borrowing capacity	400,000,000		400,000,000
Amounts outstanding under revolving credit facility	$ 0		$ 0		$ 0
Minimum interest coverage ratio for each fiscal quarter on a rolling twelve month through August 31, 2012			250.00%
Minimum interest coverage ratio for for each fiscal quarter on a rolling twelve month cumulative period from November 30, 2012 and beyond			300.00%
Actual interest coverage ratio	475.00%		475.00%
Maximum Debt to capitalization ratio			60.00%
Actual Debt to capitalization ratio	52.00%		52.00%
Revolving credit facility maturity date			December 27, 2016