Debt (Details) (USD $)	3 Months Ended	12 Months Ended
	Dec. 31, 2010	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Debt Instrument [Line Items]
Long-term Debt, Gross		$ 2,473,927,000	$ 2,381,929,000
Derivative, Fair Value, Net			35,473,000
Debt, Current		27,713,000	26,447,000
Long-term Debt, Excluding Current Maturities		2,030,030,000	1,968,274,000
Current Fiscal Year End Date		--12-31
Write Off Of Deferred Debt Issuance Cost		12,466,000	6,012,000	6,636,000
Interest Paid		90,900,000	111,100,000	110,300,000
Letters of Credit Outstanding, Amount		11,000,000
Senior Subordinated Notes 6125 due 2013 [Member]
Debt Instrument [Line Items]
Amortization of Financing Costs			200,000	700,000
6.875% Senior Subordinated Notes, Due 2015 [Member]
Debt Instrument [Line Items]
Amortization of Financing Costs			1,000,000	1,000,000
Write Off Of Deferred Debt Issuance Cost			4,000,000
Junior Subordinated Convertible Debentures [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross		345,000,000	345,000,000
Amortization of Financing Costs		200,000	200,000	200,000
Senior Term Loan [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross		419,688,000	444,375,000
3.25% Convertible Senior Debentures, Due 2035 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross		427,500,000	452,500,000
Amortization of Financing Costs		800,000	1,000,000	2,000,000
Write Off Of Deferred Debt Issuance Cost	4,600,000
3.75% Convertible Senior Subordinated Notes Due 2042 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross		390,000,000	0
Amortization of Financing Costs		100,000
3.75% Convertible Senior Subordinated Notes, due 2025 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross		318,054,000	575,000,000
Amortization of Financing Costs		400,000	600,000	100,000
Write Off Of Deferred Debt Issuance Cost		3,800,000
7.75% Senior Subordinated Notes, Due 2020 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross		550,000,000	550,000,000
Amortization of Financing Costs		1,200,000	1,100,000	600,000
Capital Lease Obligations [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross		23,685,000	15,054,000
7.75% interest rate swap agreement - fair value hedge [Member]
Debt Instrument [Line Items]
Derivative, Fair Value, Net		$ 46,090,000	$ 35,473,000