Quarterly report pursuant to Section 13 or 15(d)

Debt and Debt-Related Parties - Convertible Senior Unsecured Notes (Details)

v2.4.0.6
Debt and Debt-Related Parties - Convertible Senior Unsecured Notes (Details) (USD $)
1 Months Ended 3 Months Ended 9 Months Ended 9 Months Ended
Apr. 30, 2012
Jun. 30, 2009
Convertible Senior Unsecured Notes [Member]
Sep. 30, 2012
Convertible Senior Unsecured Notes [Member]
Jun. 30, 2012
Convertible Senior Unsecured Notes [Member]
Mar. 31, 2012
Convertible Senior Unsecured Notes [Member]
Sep. 30, 2011
Convertible Senior Unsecured Notes [Member]
Aug. 01, 2011
Convertible Senior Unsecured Notes [Member]
Jan. 01, 2009
Convertible Senior Unsecured Notes [Member]
Jul. 31, 2005
Convertible Senior Unsecured Notes [Member]
Jun. 30, 2012
Convertible Senior Unsecured Notes [Member]
Maximum [Member]
Sep. 30, 2012
Convertible Senior Unsecured Notes [Member]
Minimum [Member]
Sep. 30, 2012
Convertible Senior Unsecured Notes [Member]
Current Debt Discount [Member]
Dec. 31, 2011
Convertible Senior Unsecured Notes [Member]
Current Debt Discount [Member]
Debt Instrument [Line Items]                          
Principal amount of debt   $ 204,600,000             $ 325,000,000        
Debt instrument interest rate, stated percentage                 2.25%        
Debt instrument initial conversion rate, (in shares) per $1,000 principal amount                 28.2326        
Debt instrument conversion price (US$ per share)                 $ 35.42        
Percentage of debt principal that could be redeemed (percent)       100.00%                  
Trading period of the volume-weighted average price of stock (days)     10 days               5 days    
Volume-weighted average price of common stock (US$ per share)                   $ 53.13      
Basis spread on debt instrument variable rate (percent)     0.50%                    
Aggregate debt principal amount exchanged   120,400,000                      
Value of cash and cash equivalents debt was exchanged for 1,400,000 30,000,000                      
Number of shares of common stock exchanged for debt   4,000,000                      
Number of shares of common stock that the remaining debt principal is convertible into         5,800,000                
Debt reclassified to currrent liability           190,700,000              
Due date of Convertible Senior Unsecured Notes             12 months            
Fair value of the embedded conversion option               134,000,000          
Unamortized debt discount                       $ 0 $ 9,906,000