XML 136 R91.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Debt - 2018 Convertible Debt (Details)
1 Months Ended 12 Months Ended
Dec. 31, 2019
USD ($)
Mar. 31, 2018
USD ($)
day
$ / shares
Dec. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Debt Instrument [Line Items]          
Non-cash interest expense     $ 19,108,000 $ 10,968,000 $ 3,117,000
Convertible Senior Notes due 2023 | Convertible Debt          
Debt Instrument [Line Items]          
Debt instrument   $ 345,000,000.0      
Interest rate, stated percentage   0.00%      
Proceeds from issuance of convertible senior notes   $ 335,000,000.0      
Conversion ratio   27.5691      
Conversion price (in dollars per share) | $ / shares   $ 36.27      
Redemption price, percentage   100.00%      
If-converted value in excess of principal $ 76,400,000        
If-converted value 421,400,000        
Carrying amount of equity component 72,800,000   72,800,000    
Capitalization of debt issuance costs   $ 10,000,000.0      
Non-cash interest expense     15,200,000 12,200,000  
Unamortized debt issuance expense 5,200,000   5,200,000 6,700,000  
Level 2 | Reported Value Measurement | Convertible Senior Notes due 2023 | Convertible Debt          
Debt Instrument [Line Items]          
Long-term debt, fair value $ 310,300,000   $ 310,300,000 $ 279,100,000  
Debt Instrument, Redemption, Period One | Convertible Senior Notes due 2023 | Convertible Debt          
Debt Instrument [Line Items]          
Threshold trading days | day   20      
Threshold consecutive trading days | day   30      
Threshold percentage of stock price trigger   130.00%      
Debt Instrument, Redemption, Period Two | Convertible Senior Notes due 2023 | Convertible Debt          
Debt Instrument [Line Items]          
Threshold consecutive trading days | day   10      
Threshold percentage of stock price trigger   98.00%      
Days after threshold consecutive trading days | day   5