Compass Concierge Receivables and Allowance for Credit Losses - Summary of Activity of The ACL For concierge receivables (Detail) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning of period	$ 14.7	$ 17.3
Allowances	0.8	1.8
Net write-offs and other	(2.3)	(4.4)
End of period	$ 13.2	$ 14.7

Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
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-Publisher FASB
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
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-Section 1405
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-Publisher SEC

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
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Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 942
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
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-URI https://asc.fasb.org//1943274/2147479319/326-20-50-13

Name:	us-gaap_FinancingReceivableAllowanceForCreditLosses
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant