CREDIT ARRANGEMENTS (Narrative) (Details) (USD $)	3 Months Ended		6 Months Ended		12 Months Ended	0 Months Ended
	Feb. 28, 2015	Feb. 28, 2014	Feb. 28, 2015	Feb. 28, 2014	Aug. 31, 2012	Jun. 26, 2014	Aug. 31, 2014	May 31, 2013	Aug. 31, 2008	Jul. 31, 2007
Debt Instrument [Line Items]
Net Proceeds From Termination Of Interest Rate Swaps					$ 52,700,000
Unamortized deferred gain on termination of interest rate swaps	23,000,000		23,000,000				26,800,000
Amortization of interest rate swaps termination gain	1,900,000	1,900,000	3,799,000	3,799,000
Interest paid	33,400,000	32,800,000	42,900,000	42,300,000
CMCP
Debt Instrument [Line Items]
Revolving credit facility current borrowing capacity	58,000,000.0		58,000,000.0
Total borrowing			41,500,000
Total payments			41,500,000
$330 million notes at 4.875% due May 2023
Debt Instrument [Line Items]
Debt instrument, issuance date			May 20, 2013
Debt instrument, face amount	330,000,000.0		330,000,000.0				330,000,000	330,000,000.0
Debt instrument, interest rate, stated percentage	4.875%		4.875%				4.875%	4.875%
Debt instrument, maturity date			May 15, 2023
Redemption purchase price to principal amount, percentage								100.00%
Change of control triggering event
Debt Instrument [Line Items]
Redemption purchase price to principal amount, percentage								101.00%
$500 million notes at 7.35% due August 2018
Debt Instrument [Line Items]
Debt instrument, issuance date			Aug. 04, 2008
Debt instrument, face amount	500,000,000.0		500,000,000.0				500,000,000		500,000,000.0
Debt instrument, interest rate, stated percentage	7.35%		7.35%				7.35%		7.35%
Debt instrument, maturity date			Aug. 15, 2018
Debt instrument, effective interest rate									6.40%
$400 million notes at 6.50% due July 2017
Debt Instrument [Line Items]
Debt instrument, issuance date			Jul. 17, 2007
Debt instrument, face amount	400,000,000.0		400,000,000.0				400,000,000			400,000,000.0
Debt instrument, interest rate, stated percentage	6.50%		6.50%				6.50%			6.50%
Debt instrument, maturity date			Jul. 15, 2017
Debt instrument, effective interest rate										5.74%
Revolving credit facility
Debt Instrument [Line Items]
Revolving credit facility current borrowing capacity						350,000,000
Revolving credit facility, maturity date			Jun. 26, 2019
Revolving credit facility, maximum borrowing capacity						500,000,000
Minimum interest coverage ratio						2.50
Maximum debt to capitalization ratio						0.60
Minimum liquidity required						150,000,000
Actual interest coverage ratio	5.61		5.61
Actual debt to capitalization ratio	0.49		0.49
Revolving credit facility, amount drawn	0		0				0
Stand-by letters of credit
Debt Instrument [Line Items]
Revolving credit facility current borrowing capacity						50,000,000
Stand by letters of credit outstanding amount	$ 23,400,000		$ 23,400,000				$ 28,100,000