Segment Information - Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Segment Reporting Information
Total revenue	$ 353,386	$ 329,701	$ 266,001
Real Estate
Segment Reporting Information
Total revenue	249,272	235,124	190,792
Mortgage
Segment Reporting Information
Total revenue	12,388	10,051	6,610
Marketing Funds fees
Segment Reporting Information
Total revenue	90,319	82,391	64,402
Other.
Segment Reporting Information
Total revenue	1,407	2,135	4,197
Continuing franchise fees
Segment Reporting Information
Total revenue	133,389	118,504	90,217
Continuing franchise fees | Real Estate
Segment Reporting Information
Total revenue	123,272	110,613	84,863
Continuing franchise fees | Mortgage
Segment Reporting Information
Total revenue	10,117	7,891	5,354
Annual dues
Segment Reporting Information
Total revenue	35,676	35,549	35,075
Annual dues | Real Estate
Segment Reporting Information
Total revenue	35,676	35,549	35,075
Broker fees
Segment Reporting Information
Total revenue	62,939	65,456	50,028
Broker fees | Real Estate
Segment Reporting Information
Total revenue	62,939	65,456	50,028
Franchise sales and other revenue
Segment Reporting Information
Total revenue	31,063	27,801	26,279
Franchise sales and other revenue | Real Estate
Segment Reporting Information
Total revenue	27,385	23,506	20,826
Franchise sales and other revenue | Mortgage
Segment Reporting Information
Total revenue	$ 2,271	$ 2,160	$ 1,256