Segment Information - Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Segment Reporting Information
Total revenue	$ 91,004	$ 72,295
Real Estate
Segment Reporting Information
Total revenue	64,737	51,154
Mortgage
Segment Reporting Information
Total revenue	3,028	2,323
Marketing Funds fees
Segment Reporting Information
Total revenue	22,851	18,145
Other.
Segment Reporting Information
Total revenue	388	673
Continuing franchise fees
Segment Reporting Information
Total revenue	33,499	25,374
Continuing franchise fees | Real Estate
Segment Reporting Information
Total revenue	31,120	23,609
Continuing franchise fees | Mortgage
Segment Reporting Information
Total revenue	2,379	1,765
Annual dues
Segment Reporting Information
Total revenue	8,920	8,672
Annual dues | Real Estate
Segment Reporting Information
Total revenue	8,920	8,672
Broker fees
Segment Reporting Information
Total revenue	15,085	11,953
Broker fees | Real Estate
Segment Reporting Information
Total revenue	15,085	11,953
Franchise sales and other revenue
Segment Reporting Information
Total revenue	10,649	8,151
Franchise sales and other revenue | Real Estate
Segment Reporting Information
Total revenue	9,612	6,920
Franchise sales and other revenue | Mortgage
Segment Reporting Information
Total revenue	$ 649	$ 558