FINANCING ARRANGEMENTS (Details) (USD $)	3 Months Ended		9 Months Ended			0 Months Ended									0 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011	Jul. 30, 2012 Senior secured notes	Jul. 13, 2012 Senior secured notes	Sep. 30, 2012 Senior secured notes	Aug. 15, 2012 Senior secured notes	Jul. 16, 2012 Senior secured notes	Jun. 30, 2012 Senior secured notes	Dec. 31, 2011 Senior secured notes	Sep. 30, 2012 Senior Note at 5.25% [Member]	Dec. 31, 2011 Senior Note at 5.25% [Member]	Jul. 30, 2012 Issuance of Debt [Member] Senior secured notes	Jul. 30, 2012 Issuance of Debt [Member] Senior secured notes Redemption Period, Twelve Month Period Commencing on August 1, 2016 [Member]	Jul. 30, 2012 Issuance of Debt [Member] Senior secured notes Redemption Period, Twelve Month Period Commencing on August 1, 2017 [Member]	Jul. 30, 2012 Issuance of Debt [Member] Senior secured notes Redemption Period, Commencing on August 1, 2018 [Member]	Jul. 30, 2012 Issuance of Debt [Member] Senior secured notes Redemption Period, Prior to August 1, 2015 [Member]	Jul. 30, 2012 Issuance of Debt [Member] Senior secured notes Redemption Period, Prior to August 1, 2015 [Member] Maximum [Member]
Financing arrangements
Senior secured notes								$ 0	$ 150,900,000	$ 490,000,000	$ 520,000,000	$ 520,000,000	$ 800,000,000	$ 0
Revolving credit facility, due May 31, 2016	0		0		0
Unamortized notes premium and discount, net								0				4,203,000
Long-term obligations	800,000,000		800,000,000		524,203,000
Debt Instrument, Interest Rate, Stated Percentage						5.25%		7.625%			7.625%		5.25%
Revolving credit facility, maximum borrowing capacity	163,400,000		163,400,000
Letters of Credit Outstanding, Amount	86,600,000		86,600,000
Extinguishment of Debt, Amount						339,100,000	30,000,000
Debt Instrument, Face Amount						800,000,000
Proceeds from Issuance of Long-term Debt						262,800,000
Gains (Losses) on Extinguishment of Debt	(26,385,000)	0	(26,385,000)	0		(26,400,000)
Gains (Losses) on Extinguishment of Debt, before Write off of Deferred Debt Issuance Cost						21,100,000
Write off of Deferred Debt Issuance Cost						(5,300,000)
Unamortized Debt Issuance Expense						8,800,000
Debt Instrument, Unamortized Premium						$ 3,500,000
Interest Rate Computed On The Basis of a 360 Day Year															360 days
Interest at a Rate Computed on the Basis of Twelve 30-Day Month															30 days
Debt Instrument, Redemption Payment Term, Percentage of Principal Amount																				35.00%
Long-term Debt Redemption Price with Net Proceeds from Equity offerings as Percentage of Principal Amount																			105.25%
Long-term Debt Redemption, Price as Percentage of Principal Amount																102.625%	101.313%	100.00%	100.00%
Long-term Debt Redemption Price Due to Change of Control as Percentage of Principal Amount																			101.00%