Business and Organization (Details)	12 Months Ended
	Dec. 31, 2020 country state Office class item Vote	Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Number of classes of common stock | class	2
RMCO, LLC
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Parent economic interest in RMCO (as a percent)	59.40%	58.70%
RIHI | RMCO, LLC
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Non-controlling interest ownership of common units in RMCO as a percentage	40.60%	41.30%
Minimum
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Number of agents | item	135,000
Number of offices	8,000
Number of countries in which entity operates | country	110
Minimum | Motto Mortgage
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Number of offices	125
Number of states in which entity operates | state	30
REMAX
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Percentage of Company consisting of franchises	100.00%
Common Class A
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Number of votes per share held | Vote	1
Common Class A | One Company Founder [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Ownership percentage	1.10%
Common Class B | RIHI
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Ownership percentage	40.60%