Convertible Senior Notes - Other Key Terms and Premiums Paid for Capped Calls (Details) - Capped Calls - USD ($) $ / shares in Units, $ in Thousands	Jun. 05, 2020	Sep. 21, 2018
2023 Notes and 2025 Notes
Option Indexed to Issuer's Equity [Line Items]
Initial strike price, subject to certain adjustments (in dollars per share)		$ 148.30
Cap price, subject to certain adjustments (in dollars per share)		$ 232.62
Total premium paid		$ 274,275
2027 Notes
Option Indexed to Issuer's Equity [Line Items]
Initial strike price, subject to certain adjustments (in dollars per share)	$ 255.34
Cap price, subject to certain adjustments (in dollars per share)	$ 378.28
Total premium paid	$ 137,379