Stock-based Payments - Summary of Time-based Stock Options (Details) - Time-Based Options - $ / shares shares in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Number of Options
Outstanding, beginning balance (in shares)	2.6
Exercised (in shares)	(0.1)
Forfeited (in shares)	(0.1)
Outstanding, ending balance (in shares)	2.4	2.6
Exercisable (in shares)	3.7
Weighted Average Exercise Price per Share
Outstanding, beginning balance (in dollars per share)	$ 11.51
Exercised (in dollars per share)	10.04
Forfeited (in dollars per share)	13.93
Outstanding, ending balance (in dollars per share)	11.51	$ 11.51
Weighted average exercise price per share, exercisable (in dollars per share)	$ 11.42
Weighted average remaining contractual term, outstanding	5 years 1 month 6 days	5 years 10 months 24 days
Weighted average remaining contractual term, exercisable	5 years 1 month 6 days