Business and Organization (Details)	12 Months Ended
	Dec. 31, 2018 country Vote Office class item	Dec. 31, 2017
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)	58.57%	58.49%
Non-controlling unitholders ownership of common units in RMCO as a percentage	41.43%	41.51%
RIHI | RMCO, LLC
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Non-controlling unitholders ownership of common units in RMCO as a percentage	41.43%
Common Class A
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Number of votes per share held | Vote	1
Common Class B | RIHI
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Ratio of votes in parent company to number of L L C common units held	2
Minimum
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Number of agents | item	120,000
Number of offices | Office	8,000
Number of countries in which entity operates | country	110
REMAX [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Percentage of Company consisting of franchises	100.00%