Long-Term Debt (Schedule Of Long-term Debt Instruments) (Details) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
Senior secured credit facility	$ 34,100
Total debt	2,056,741	1,862,559
Unamortized deferred gain - terminated interest rate swaps	23,119	27,635
Current portion of long-term debt	(149,331)	(143,478)
Long-term debt	1,930,529	1,746,716
Convertible Debentures [Member]
Convertible debentures, net of unamortized discount	149,331	143,478
Senior Notes Due 2015 [Member]
Senior notes	434,812	470,866
Senior Notes Due 2016 [Member]
Senior notes	576,334	583,605
Senior Notes Due 2019 [Member]
Senior notes	291,922	293,496
Senior Subordinated Notes Due 2016 [Member]
Senior notes	350,000	350,000
U.S. Credit Facility [Member]
Senior secured credit facility	137,000
Canadian Credit Facility [Member]
Senior secured credit facility	$ 117,342

Including the current and noncurrent portions, carrying amount of debt identified as being convertible into another form of financial instrument (typically the entity's common stock) as of the balance sheet date, which originally required full repayment more than twelve months after issuance or greater than the normal operating cycle of the company.

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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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Amount as of the balance sheet date of the unamortized adjustment to the carrying value of an interest-bearing hedged item made under an effective interest rate fair value hedge that is amortized upon discontinuation of the interest rate fair value hedge.

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Amount borrowed under the credit facility as of the balance sheet date.

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Total of the portions of the carrying amounts as of the balance sheet date of long-term debt, which may include notes payable, bonds payable, debentures, mortgage loans, and commercial paper, which are scheduled to be repaid within one year or the normal operating cycle, if longer, and after deducting unamortized discount or premiums, if any.

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Sum of the carrying values as of the balance sheet date of all long-term debt, which is debt initially having maturities due after one year from the balance sheet date or beyond the operating cycle, if longer, but excluding the portions thereof scheduled to be repaid within one year (current maturities) or the normal operating cycle, if longer, and after deducting unamortized discount or premiums, if any.

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Including the current and noncurrent portions, carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer). Senior note holders are paid off in full before any payments are made to junior note holders.

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