Ownership, Description of Business, and Summary of Significant Accounting Policies - Additional Information (Details) - USD ($) shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Restricted cash	$ 20.3	$ 25.0
Anti-dilutive employee stock options outstanding (in shares)	51	64	66