Summary of Significant Accounting Policies - Disaggregated revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Disaggregation of Revenue [Line Items]
Total revenue	$ 85,401	$ 91,004
Franchise sales and other revenue
Disaggregation of Revenue [Line Items]
Total revenue	12,473	10,649
Real Estate
Disaggregation of Revenue [Line Items]
Total revenue	60,630	64,737
Real Estate | Fee revenue
Disaggregation of Revenue [Line Items]
Total revenue	49,057	55,125
Real Estate | Franchise sales and other revenue
Disaggregation of Revenue [Line Items]
Total revenue	11,573	9,612
Marketing Funds
Disaggregation of Revenue [Line Items]
Total revenue	21,342	22,851
Mortgage
Disaggregation of Revenue [Line Items]
Total revenue	3,188	3,028
Mortgage | Franchise sales and other revenue
Disaggregation of Revenue [Line Items]
Total revenue	659	649
Other.
Disaggregation of Revenue [Line Items]
Total revenue	241	388
U.S. | Company -Owned Regions | Fee revenue
Disaggregation of Revenue [Line Items]
Total revenue	33,861	39,154
U.S. | Independent Regions | Fee revenue
Disaggregation of Revenue [Line Items]
Total revenue	1,476	1,701
U.S. | Marketing Funds
Disaggregation of Revenue [Line Items]
Total revenue	16,305	17,559
Canada | Company -Owned Regions | Fee revenue
Disaggregation of Revenue [Line Items]
Total revenue	9,798	10,475
Canada | Independent Regions | Fee revenue
Disaggregation of Revenue [Line Items]
Total revenue	724	703
Canada | Marketing Funds
Disaggregation of Revenue [Line Items]
Total revenue	4,763	5,013
Global | Global. | Fee revenue
Disaggregation of Revenue [Line Items]
Total revenue	3,198	3,092
Global | Marketing Funds
Disaggregation of Revenue [Line Items]
Total revenue	$ 274	$ 279