Disaggregation of Revenue - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Monthly resident fees	$ 50.6	$ 49.7
Revenue recognized	82.1
Additions for allowance for doubtful accounts	17.6
Deferred Revenue and Credits
Disaggregation of Revenue [Line Items]
Deferred revenue	$ 106.4	$ 112.4

Contract With Customer, Liability, Deferred Revenue, Monthly Resident Fees

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- Definition

Amount of increase (decrease) in the allowance for doubtful accounts.

+ References

No definition available.

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- Definition

Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 45
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-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130549-203045

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- Definition

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.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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