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) (Convertible Senior Unsecured Notes [Member], USD $)
3 Months Ended 3 Months Ended
Mar. 31, 2012
Jun. 30, 2009
Sep. 30, 2011
Aug. 01, 2011
Jan. 01, 2009
Jul. 31, 2005
Mar. 31, 2012
Maximum [Member]
Mar. 31, 2012
Minimum [Member]
Mar. 31, 2012
Current Debt Discount [Member]
Dec. 31, 2010
Current Debt Discount [Member]
Debt Instrument [Line Items]                    
Debt Instrument, Face Amount   $ 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           $ 35.42        
Redemption of Debt Instrument, Percentage 100.00%                  
Debt Instrument, Trading Period (days) 10 days             5 days    
Volume-weighted average price of common stock             $ 53.13      
Debt Instrument, Basis Spread on Variable Rate 0.50%                  
Debt Conversion, Original Debt, Amount   120,400,000                
Debt Conversion, Converted Instrument, Amount   30,000,000                
Debt Conversion, Converted Instrument, Shares Issued   4,000,000                
Debt Instrument, Convertible, Number of Equity Instruments, in shares 5,800,000                  
Long-term Debt, Current Maturities     190,700,000              
Duration of Convertible Senior Unsecured Notes       12 months            
Convertible Debt, Fair Value Disclosures         134,000,000          
Debt Instrument, Unamortized Discount                 $ 5,700,000 $ 9,906,000