FINANCING ARRANGEMENTS (Details) (USD $)	Mar. 31, 2012	Dec. 31, 2011
Financing arrangements
Revolving credit facility, due May 31, 2016	$ 0
Long-term obligations	523,833,000	524,203,000
Revolving credit facility, maximum borrowing capacity	164,800,000
Letters of Credit Outstanding, Amount	85,200,000
Senior secured notes
Financing arrangements
Senior secured notes, at 7.625%, due on August 15, 2016	520,000,000	520,000,000
Debt Instrument, Interest Rate, Stated Percentage	7.625%
Revolving credit facility, due May 31, 2016
Unamortized notes premium and discount, net	3,833,000	4,203,000
Long-term obligations	$ 523,833,000	$ 524,203,000

Including current and noncurrent portions, aggregate carrying amount of long-term borrowings as of the balance sheet date before deducting unamortized discount or premiums (if any). May include notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt, which had initial maturities beyond one year or beyond the normal operating cycle, if longer.

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