Non-controlling Interest - Ownership of common units in RMCO (Details) - RMCO, LLC - shares	Mar. 31, 2021	Dec. 31, 2020
Shares
Holdings outstanding Class A common stock (equal to Holdings common units in RMCO)	18,719,248	18,390,691
Total number of common stock units in RMCO	31,278,848	30,950,291
Ownership Percentage
Holdings outstanding Class A common stock (equal to Holdings common units in RMCO) (as a percentage)	59.80%	59.40%
Total percentage of common stock units	100.00%	100.00%
RIHI
Shares
Non-controlling interest ownership of common units in RMCO	12,559,600	12,559,600
Ownership Percentage
Non-controlling interest ownership of common units in RMCO (as a percentage)	40.20%	40.60%

The noncontrolling interest in net assets of the subsidiary, in number of common stock units owned.

No definition available.

Name:	rmax_MinorityInterestNumberOfStockUnitsOwnedByNoncontrollingOwners
Namespace Prefix:	rmax_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

The parent entity's interest in net assets of the subsidiary, in number of common stock units owned.

No definition available.

Name:	rmax_MinorityInterestNumberOfStockUnitsOwnedByParent
Namespace Prefix:	rmax_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

No definition available.

Name:	rmax_OwnershipPercentageAbstract
Namespace Prefix:	rmax_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Aggregate percentage of subsidiary's common units outstanding.

No definition available.

Name:	rmax_PercentageOfCommonUnits
Namespace Prefix:	rmax_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

No definition available.

Number of common units of ownership outstanding of a limited liability company (LLC).

No definition available.

Name:	us-gaap_CommonUnitOutstanding
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

No definition available.

Name:	us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

No definition available.

Name:	us-gaap_MinorityInterestOwnershipPercentageByParent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

Name:	srt_OwnershipAxis=rmax_RMCOLlcMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	dei_LegalEntityAxis=rmax_RihiIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: