Summary of Significant Accounting Policies - Disaggregated revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Disaggregation of Revenue [Line Items]
Total revenue	$ 81,223	$ 88,943	$ 249,071	$ 272,119
Franchise sales and other revenue
Disaggregation of Revenue [Line Items]
Total revenue	5,825	7,390	24,659	24,841
Real Estate
Disaggregation of Revenue [Line Items]
Total revenue	56,563	62,655	174,752	193,168
Real Estate | Fee revenue
Disaggregation of Revenue [Line Items]
Total revenue	51,751	56,189	153,103	171,266
Real Estate | Franchise sales and other revenue
Disaggregation of Revenue [Line Items]
Total revenue	4,812	6,466	21,649	21,902
Marketing Funds
Disaggregation of Revenue [Line Items]
Total revenue	20,853	22,736	63,272	68,496
Mortgage
Disaggregation of Revenue [Line Items]
Total revenue	3,640	3,194	10,444	9,337
Mortgage | Franchise sales and other revenue
Disaggregation of Revenue [Line Items]
Total revenue	846	566	2,407	1,821
Other.
Disaggregation of Revenue [Line Items]
Total revenue	167	358	603	1,118
U.S. | Company -Owned Regions | Fee revenue
Disaggregation of Revenue [Line Items]
Total revenue	35,504	39,975	105,440	121,862
U.S. | Independent Regions | Fee revenue
Disaggregation of Revenue [Line Items]
Total revenue	1,668	1,819	4,896	5,397
U.S. | Marketing Funds
Disaggregation of Revenue [Line Items]
Total revenue	15,638	17,186	48,043	52,386
Canada | Company -Owned Regions | Fee revenue
Disaggregation of Revenue [Line Items]
Total revenue	10,607	10,764	30,946	32,673
Canada | Independent Regions | Fee revenue
Disaggregation of Revenue [Line Items]
Total revenue	721	723	2,168	2,141
Canada | Marketing Funds
Disaggregation of Revenue [Line Items]
Total revenue	4,956	5,201	14,440	15,202
Global | Global. | Fee revenue
Disaggregation of Revenue [Line Items]
Total revenue	3,251	2,908	9,653	9,193
Global | Marketing Funds
Disaggregation of Revenue [Line Items]
Total revenue	$ 259	$ 349	$ 789	$ 908