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Convertible Senior Notes - Narrative (Details) - Convertible debt - 3.00% Convertible senior notes due 2022
 1 Months Ended 3 Months Ended
Aug. 31, 2015
USD ($)
item
$ / shares
Mar. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Long-term debt      
Debt principal amount $ 150,000,000.0 $ 150,000,000 $ 150,000,000
Interest rate 3.00%    
Net proceeds from issuance of convertible notes $ 145,400,000    
Trading days, number | item 20    
Consecutive trading days, period 30 days    
Stock price trigger 130.00%    
Business days, period 5 days    
Consecutive trading-day period 5 days    
Common stock per principal amount $ 1,000    
Maximum product of the closing sale price of shares of the Company's common stock and the applicable conversion rate for such trading day 98.00%    
Conversion ratio 17.7487    
Conversion price per share (in dollars per share) | $ / shares $ 56.34    
Convertible instruments principal and unpaid interest payable upon events of default 100.00%    
Minimum percentage of principal held by convertible debt instrument holders required to issue notice for declaration of principal and unpaid interest payable upon events of default 25.00%    
Term of the convertible notes 7 years    
Adjustments to additional paid in capital, equity component of convertible debt $ 57,500,000    
Net deferred tax liability in connection with convertible notes $ 22,300,000    
Fair value of convertible notes   $ 95,900,000  
Remaining contractual life of the convertible notes   5 years 4 months 17 days  
Redemption on or after August 20, 2018      
Long-term debt      
Trading days, number | item 19    
Consecutive trading days, period 30 days    
Stock price trigger 130.00%    
Redemption price 100.00%    
Sinking fund $ 0