Revenue Recognition - Deferred Revenue (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenue Recognition [Abstract]
Balance at beginning of period	$ 123.7	$ 89.8	$ 107.1	$ 81.6
New contracts sold	13.5	15.8	52.1	42.6
Less: reductions for revenue recognized	(11.7)	(7.3)	(33.7)	(25.9)
Balance at end of period	$ 125.5	$ 98.3	$ 125.5	$ 98.3

Amount of deferred revenue recognized for transactions arising during the current reporting period. Deferred revenue is a liability as of the balance sheet date related to a revenue producing activity for which revenue has not yet been recognized. Generally, an Entity records deferred revenue when it receives consideration from a customer before achieving certain criteria that must be met for revenue to be recognized in conformity with GAAP.

No definition available.

Name:	us-gaap_DeferredRevenueAdditions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration