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Convertible Senior Notes (Details) - Senior Notes - Convertible Debt
$ / shares in Units, $ in Thousands
1 Months Ended
Mar. 31, 2018
day
shares
Jan. 31, 2021
USD ($)
$ / shares
Jul. 31, 2020
USD ($)
Debt Instrument [Line Items]      
Aggregate principal amount | $   $ 400,000 $ 400,000
Stated interest rate 1.25%    
On or after October 15, 2024      
Debt Instrument [Line Items]      
Number of shares issuable per 1,000 principal converted (in shares) | shares 8.7912    
Conversion price (in dollars per share) | $ / shares   $ 113.75  
On or after March 20, 2022      
Debt Instrument [Line Items]      
Debt instrument, redemption, percent 100.00%    
Threshold percentage of stock price trigger 130.00%    
Threshold trading days | day 20    
Conversion notice period 30 days