Debt (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Debt and capital lease obligations related to continuing operations
Debt Outstanding	$ 1,073,825	$ 1,159,215
Less amounts due within one year	(755)	(58,574)
Total long-term debt	1,073,070	1,100,641
Convertible Notes Payable [Member]
Debt and capital lease obligations related to continuing operations
Debt Outstanding	319,246	306,551
Capital Lease Obligations [Member]
Debt and capital lease obligations related to continuing operations
Debt Outstanding	2,399	484
$925 Million Credit Facility [Member]
Debt and capital lease obligations related to continuing operations
Debt Outstanding	600,000	0
$1.0 Billion Credit Facility [Member]
Debt and capital lease obligations related to continuing operations
Debt Outstanding	0	700,000
Senior Notes, 6.75%, Due 2014 [Member]
Debt and capital lease obligations related to continuing operations
Debt Outstanding	$ 152,180	$ 152,180