Stock-based Compensation Expense and Share Repurchase Programs - Unrecognized Stock-based Compensation Expense (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2020 USD ($)
Restricted stock units (including PSUs)
Type of award:
Unrecognized Expense	$ 487,254
Weighted-average Recognition Period	2 years 21 days
Stock options
Type of award:
Unrecognized Expense	$ 76,261
Weighted-average Recognition Period	1 year 11 months 12 days
ESPP share issuances
Type of award:
Unrecognized Expense	$ 3,265
Weighted-average Recognition Period	5 months 8 days