Stock-Based Compensation - RSUs (Details) - RSUs shares in Thousands	12 Months Ended
	Dec. 31, 2020 $ / shares shares
Number of Units
Outstanding, beginning balance (in shares) | shares	11,285
Granted (in shares) | shares	9,301
Vested (in shares) | shares	(5,066)
Forfeited (in shares) | shares	(1,228)
Outstanding, ending balance (in shares) | shares	14,292
Weighted Average Grant Date Fair Value Per Unit
Unvested, beginning balance (in dollars per share) | $ / shares	$ 27.26
Granted (in dollars per share) | $ / shares	22.33
Vested (in dollars per share) | $ / shares	29.02
Forfeited (in dollars per share) | $ / shares	24.18
Unvested, ending balance (in dollars per share) | $ / shares	$ 23.70