XML 59 R70.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Long-Term Debt - Convertible Senior Notes Due 2022 (Details)
$ / shares in Units, $ in Thousands
12 Months Ended
Nov. 01, 2016
USD ($)
$ / shares
Dec. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Debt Instrument [Line Items]        
Principal amount   $ 436,146    
Unamortized debt discount   (22,540) $ (28,802)  
Interest expense   31,186 32,617 $ 38,274
Convertible Senior Notes Maturing May 2022        
Debt Instrument [Line Items]        
Principal amount $ 125,000 125,000 125,000  
Interest rate (as a percent) 4.25%      
Frequency of periodic payment semi-annually      
Maturity date May 01, 2022      
Initial conversion ratio 0.0719748      
Initial conversion price per share (in dollars per share) | $ / shares $ 13.89      
Redemption price as a percentage of principal amount 100.00%      
Minimum percentage in aggregate principal amount 25.00%      
Unamortized debt discount $ (16,900) (7,999) (11,000)  
Carrying amount of equity component $ 11,000      
Effective interest rate (as a percent) 7.30%      
Interest expense   $ 8,400 $ 8,100 $ 7,900