Quarterly report pursuant to Section 13 or 15(d)

Financing Arrangements (Narrative) (Details)

v3.5.0.2
Financing Arrangements (Narrative) (Details)
1 Months Ended 3 Months Ended
Aug. 31, 2014
USD ($)
d
$ / shares
shares
Mar. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Debt Instrument [Line Items]      
Initial debt value   $ 204,653,000 $ 201,985,000
Common stock, shares available to be issued | shares 3,264,643    
Exercise price of convertible bond hedge | $ / shares $ 75.05    
Exercise price | $ / shares $ 125.08    
Proceeds from issuance of warrants $ 11,600,000    
2019 convertible senior notes      
Debt Instrument [Line Items]      
Aggregate principal amount outstanding   245,000,000 245,000,000
Initial debt value   207,831,000 205,372,000
Senior Notes      
Debt Instrument [Line Items]      
Payment for convertible bond hedges $ 48,100,000    
Senior Notes | 2019 convertible senior notes      
Debt Instrument [Line Items]      
Interest rate 0.75%    
Aggregate principal amount outstanding $ 245,000,000.0    
Net proceeds from note after debt issuance costs $ 239,300,000    
Initial conversion rate 0.0133251    
Initial conversion price | $ / shares $ 75.05    
Proceeds from issuance of debt $ 245,000,000    
Debt discount rate 5.83%    
Initial debt value $ 192,500,000    
If-converted value in excess of principal   104,600,000  
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 $ 4,500,000    
Term of notes 5 years    
Carrying value of the equity component of debt, net of issuance costs   $ 51,300,000 $ 51,300,000
Senior Notes | 2019 convertible senior notes | Debt Instrument, Redemption, Period One      
Debt Instrument [Line Items]      
Threshold trading days | d 20    
Consecutive trading days 30 days    
Percentage of stock price trigger 130.00%    
Senior Notes | 2019 convertible senior notes | Debt Instrument, Redemption, Period Two      
Debt Instrument [Line Items]      
Threshold trading days | d 5    
Consecutive trading days 10 days    
Maximum threshold percentage of debt trading price trigger 98.00%