Business and Organization (Details)	Sep. 30, 2018 country Office item	Dec. 31, 2017
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Number of agents | item	120,000
Number of offices | Office	7,000
Number of countries in which entity operates | country	100
RMCO, LLC
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Parent economic interest in RMCO (as a percent)	58.56%	58.49%
Non-controlling unitholders ownership of common units in RMCO as a percentage	41.44%	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	41.44%