Annual report pursuant to Section 13 and 15(d)

Debt (Convertible Notes) (Details)

v3.20.4
Debt (Convertible Notes) (Details)
1 Months Ended 12 Months Ended
May 25, 2018
USD ($)
day
$ / shares
Dec. 15, 2014
Aug. 31, 2020
USD ($)
day
$ / shares
May 31, 2018
USD ($)
Dec. 31, 2020
USD ($)
$ / shares
Dec. 31, 2019
USD ($)
$ / shares
Dec. 31, 2018
USD ($)
Debt Instrument [Line Items]              
Accretion of debt discount         $ 14,084,000 $ 15,040,000 $ 11,134,000
Convertible Notes due 2023              
Debt Instrument [Line Items]              
Face amount $ 345,000,000     $ 345,000,000 345,000,000 $ 345,000,000  
Net proceeds from offering       $ 335,018,000      
Interest rate 1.75%            
Issuance costs         8,593,000    
Repurchase percentage of principal 100.00%            
Conversion rate 0.0146381            
Conversion price (in dollars per share) | $ / shares $ 68.31         $ 68.31  
Threshold trading days | day 20            
Consecutive trading days | day 30            
Threshold business days   5 days          
Threshold consecutive trading-day period   5 days          
Threshold percentage of trading price trigger 98.00%            
Allocated to equity components $ 46,611,000            
Offering costs 1,389,000            
Discount $ 48,000,000       24,058,000 $ 33,491,000  
Accretion of debt discount         $ 9,434,000 $ 9,150,000  
Threshold percentage of stock price trigger 130.00%            
Effective interest rate         6.00% 6.00%  
Convertible Notes due 2025              
Debt Instrument [Line Items]              
Face amount     $ 517,500,000   $ 517,500,000 $ 0  
Net proceeds from offering     $ 502,960,000        
Interest rate     0.75%        
Repurchase percentage of principal     100.00%        
Conversion rate 0.0093682            
Conversion price (in dollars per share) | $ / shares     $ 106.74   $ 106.74    
Threshold trading days | day     20        
Consecutive trading days | day     30        
Threshold business days     5 days        
Threshold consecutive trading-day period     5 days        
Threshold percentage of trading price trigger     98.00%        
Allocated to equity components     $ 61,859,000        
Offering costs     1,982,000        
Taxes     6,712,000        
Discount     $ 70,552,000   $ 65,902,000 $ 0  
Accretion of debt discount         $ 4,650,000    
Threshold percentage of stock price trigger     130.00%        
Effective interest rate         4.00%    
Convertible Notes due 2025 | Other non-current assets              
Debt Instrument [Line Items]              
Issuance costs     $ 12,558,000