Common Stock (Narrative) (Details) (USD $)	Dec. 31, 2012	Dec. 31, 2011	Nov. 30, 2009
Class of Stock [Line Items]
Common stock, shares authorized	500,000,000	500,000,000
Common stock, par value	$ 0.01	0.01
Number of shares available for grant	2,900,000
Employee Stock Option [Member]
Class of Stock [Line Items]
Common stock, capital shares reserved for future issuance	1,300,000	1,500,000
QUIPS [Member]
Class of Stock [Line Items]
Common stock, capital shares reserved for future issuance	1,300,000	1,300,000
Convertible subordinated notes - 1 7/8 percent [Member]
Class of Stock [Line Items]
Common stock, capital shares reserved for future issuance	0	1,000,000
4 percent Convertible Senior Notes [Member]
Class of Stock [Line Items]
Common stock, capital shares reserved for future issuance	18,900,000	18,900,000
4 percent Convertible Senior Notes [Member]
Class of Stock [Line Items]
Stated interest rate	4.00%	4.00%	4.00%
Debt instrument, convertible, conversion price	$ 11.11
Convertible subordinated notes - 1 7/8 percent [Member]
Class of Stock [Line Items]
Stated interest rate	1.875%
Time and Performance Based Restricted Stock Units [Member]
Class of Stock [Line Items]
Restricted stock units outstanding	1,400,000