Revenue Recognition - Change in Contract Liabilities (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Revenue from Contract with Customer [Abstract]
Balance as of January 1	$ 268.3	$ 247.4
Revenue recognized	(32.0)	(28.8)
Revenue deferred	38.7	40.2
Balance as of June 30	$ 275.0	$ 258.8