Fair Value (Schedule of Long Term Debt Instruments) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Gross	$ 2,381,929	$ 2,561,461
Long-term Debt	2,381,929
Debt Instrument, Unamortized Discount	(422,681)	(446,876)
Senior Subordinated Notes 6125 due 2013 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Gross	0	250,000
Long-term Debt, Fair Value	0	251,300
6.875% Senior Subordinated Notes, Due 2015 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Gross	0	525,000
Long-term Debt, Fair Value	0	535,500
7.75% Senior Subordinated Notes, Due 2020 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Gross	550,000	400,000
Long-term Debt, Fair Value	591,300	415,500
Convertible Subordinated Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Gross	575,000	575,000
Long-term Debt, Fair Value	816,500	636,400
Long-term Debt	361,345	353,505
Debt Instrument, Unamortized Discount	213,655	221,495
Junior Subordinated Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Gross	345,000	345,000
Long-term Debt, Fair Value	318,800	266,900
Long-term Debt	203,675	201,282
Debt Instrument, Unamortized Discount	141,325	143,718
3.25% Convertible Senior Debentures, Due 2035 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Gross	452,500	452,500
Long-term Debt, Fair Value	404,600	427,600
Long-term Debt	384,799	370,837
Debt Instrument, Unamortized Discount	$ 67,701	$ 81,663