Convertible Senior Notes Due 2023 - Narrative (Details)	12 Months Ended
	Dec. 31, 2020 USD ($) day $ / shares Rate shares	Dec. 31, 2019 USD ($)
Debt Instrument [Line Items]
Strike price of the warrant transactions (in dollars per share) | $ / shares	$ 80.9063
Convertible Debt
Debt Instrument [Line Items]
Interest rate (as a percent)	0.625%
Effective interest rate (as percent)	5.41%
Principal amount of debt | $	$ 402,500,000	$ 402,500,000
Conversion rate for the notes (in shares per $1,000 principal amount)	0.0168545
Conversion price (in dollars per share) | $ / shares	$ 59.33
Convertible note hedge options issued (in shares) | shares	402,500
Common stock issued upon conversion of Notes (in shares) | shares	6,800,000
Warrants issued (in shares) | shares	6,783,939
Number of warrants (in shares) | shares	1
Conversion of debt to equity | $	$ 0	$ 0
Convertible Debt | Conversion Circumstance One
Debt Instrument [Line Items]
Threshold trading days (whether or not consecutive) | day	20
Consecutive trading day period (in days) | day	30
Conversion rate of the notes on trading day (as percent)	130.00%
Conversion option stock price trigger (in dollars per share) | $ / shares	$ 77.13
Convertible Debt | Conversion Circumstance Two
Debt Instrument [Line Items]
Threshold trading days (whether or not consecutive) | day	5
Consecutive trading day period (in days) | day	10
Conversion rate of the notes on trading day (as percent) | Rate	98.00%