Annual report pursuant to Section 13 and 15(d)

Debt (Conv) (Details)

v3.3.1.900
Debt (Conv) (Details) - Convertible Notes
 12 Months Ended
Dec. 15, 2014
USD ($)
item
$ / shares
Dec. 31, 2015
USD ($)
$ / shares
Dec. 31, 2014
USD ($)
Debt      
Face amount $ 172,500,000    
Net proceeds from offering $ 166,967,000    
Interest rate (as a percent) 1.75% 1.75%  
Repurchase percentage of principal (as a percent) 100.00%    
Conversion rate 0.0159022    
Principal amount | $ / shares $ 1,000    
Conversion price (in dollars per share) | $ / shares $ 62.88 $ 62.88  
Threshold trading days (in days) | item 20    
Consecutive trading days 30 days    
Threshold percentage of stock price trigger (as a percent) 130.00%    
Threshold business days 5 days    
Threshold consecutive trading-day period 5 days    
Threshold percentage of trading price trigger (as a percent) 98.00%    
Allocated to equity components $ 26,618,000    
Offering costs 882,000    
Discount $ 27,500,000 $ 22,367,000 $ 27,297,000
Accretion of debt discount   $ 4,932,000 203,000
Effective interest rate on the liability component (as a percent)   6.00%  
Other non-current assets      
Debt      
Issuance costs     $ 4,651,000