Quarterly report pursuant to Section 13 or 15(d)

Financing Arrangements (Narrative) (Details)

v2.4.0.8
Financing Arrangements (Narrative) (Details) (USD $)
1 Months Ended 9 Months Ended 1 Months Ended
Aug. 31, 2014
Sep. 30, 2014
Sep. 30, 2013
Jul. 31, 2014
Dec. 31, 2013
Aug. 12, 2014
Common Stock
Sep. 30, 2014
2019 convertible senior notes
Dec. 31, 2013
2019 convertible senior notes
Aug. 31, 2014
Senior Notes
Aug. 31, 2014
Senior Notes
2019 convertible senior notes
Aug. 31, 2014
Senior Notes
2019 convertible senior notes
Debt Instrument, Redemption, Period One
D
Aug. 31, 2014
Senior Notes
2019 convertible senior notes
Debt Instrument, Redemption, Period Two
D
Debt Instrument [Line Items]                        
Proceeds from issuance of debt                   $ 245,000,000    
Aggregate principal amount outstanding             245,000,000 0   245,000,000    
Debt discount rate                   5.83%    
Initial debt value   193,631,000     0   193,631,000 0   192,500,000    
Additional final payment on borrowings       6.00%                
Net proceeds from note after debt issuance costs                   239,300,000    
Initial conversion rate                   0.0133251    
Initial conversion price                   $ 75.05    
Premium percentage                   35.00%    
Share price           $ 55.59            
Interest rate                   0.75%    
Threshold trading days                     20 5
Consecutive trading days                     30 days 10 years
Percentage of stock price trigger                     130.00%  
Maximum threshold percentage of debt trading price trigger                       98.00%
Debt issuance costs                   5,700,000    
Equity component of convertible debt recorded as a reduction to additional paid-in capital                   1,200,000    
Long-term debt issuance costs   3,598,000     0         4,500,000    
Term of notes                   5 years    
Carrying value of the equity component of debt, net of issuance costs                   51,300,000    
Exercise price $ 125.08                      
Payment for convertible bond hedges   48,143,000 0           48,143,000      
Common stock, shares available to be issued 3,264,643                      
Exercise Price of Convertible Bond Hedge $ 75.05                      
Proceeds from issuance of warrants $ 11,600,000