Segment Information - Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Segment Reporting Information
Total revenue	$ 92,172	$ 77,246	$ 183,176	$ 149,541
Real Estate
Segment Reporting Information
Total revenue	65,776	56,291	130,513	107,445
Mortgage
Segment Reporting Information
Total revenue	3,115	2,410	6,143	4,733
Marketing Funds fees
Segment Reporting Information
Total revenue	22,909	18,042	45,760	36,187
Other.
Segment Reporting Information
Total revenue	372	503	760	1,176
Continuing franchise fees
Segment Reporting Information
Total revenue	34,128	26,955	67,627	52,329
Continuing franchise fees | Real Estate
Segment Reporting Information
Total revenue	31,619	25,039	62,739	48,648
Continuing franchise fees | Mortgage
Segment Reporting Information
Total revenue	2,509	1,916	4,888	3,681
Annual dues
Segment Reporting Information
Total revenue	9,016	8,869	17,936	17,541
Annual dues | Real Estate
Segment Reporting Information
Total revenue	9,016	8,869	17,936	17,541
Broker fees
Segment Reporting Information
Total revenue	19,317	17,453	34,402	29,406
Broker fees | Real Estate
Segment Reporting Information
Total revenue	19,317	17,453	34,402	29,406
Franchise sales and other revenue
Segment Reporting Information
Total revenue	6,802	5,927	17,451	14,078
Franchise sales and other revenue | Real Estate
Segment Reporting Information
Total revenue	5,824	4,930	15,436	11,850
Franchise sales and other revenue | Mortgage
Segment Reporting Information
Total revenue	$ 606	$ 494	$ 1,255	$ 1,052