Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130549-203045

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

Revenue Recognition - Additional Information (Details) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2020 Center	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)
Disaggregation of Revenue [Line Items]
Deferred revenue, revenue recognized \| $		$ 170.0	$ 155.1
Canada
Disaggregation of Revenue [Line Items]
Number of centers divested \| Center	2