Summary of Significant Accounting Policies - Disaggregated revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Total revenue	$ 329,701	$ 266,001	$ 282,293
Franchise sales and other revenue
Disaggregation of Revenue [Line Items]
Total revenue	27,801	26,279	28,667
Real Estate
Disaggregation of Revenue [Line Items]
Total revenue	235,124	190,792	199,636
Real Estate | Fee revenue
Disaggregation of Revenue [Line Items]
Total revenue	211,618	169,966	177,253
Real Estate | Franchise sales and other revenue
Disaggregation of Revenue [Line Items]
Total revenue	23,506	20,826	22,383
Marketing Funds
Disaggregation of Revenue [Line Items]
Total revenue	82,391	64,402	72,299
Mortgage
Disaggregation of Revenue [Line Items]
Total revenue	10,051	6,610	4,542
Mortgage | Franchise sales and other revenue
Disaggregation of Revenue [Line Items]
Total revenue	2,160	1,256	468
Other.
Disaggregation of Revenue [Line Items]
Total revenue	2,135	4,197	5,816
U.S. | Company -Owned Regions | Fee revenue
Disaggregation of Revenue [Line Items]
Total revenue	154,981	126,406	132,670
U.S. | Independent Regions | Fee revenue
Disaggregation of Revenue [Line Items]
Total revenue	11,392	13,345	13,380
U.S. | Marketing Funds
Disaggregation of Revenue [Line Items]
Total revenue	68,662	57,974	64,906
Canada | Company -Owned Regions | Fee revenue
Disaggregation of Revenue [Line Items]
Total revenue	27,234	12,659	13,647
Canada | Independent Regions | Fee revenue
Disaggregation of Revenue [Line Items]
Total revenue	6,510	8,301	8,187
Canada | Marketing Funds
Disaggregation of Revenue [Line Items]
Total revenue	12,722	5,634	6,559
Global | Global. | Fee revenue
Disaggregation of Revenue [Line Items]
Total revenue	11,501	9,255	9,369
Global | Marketing Funds
Disaggregation of Revenue [Line Items]
Total revenue	$ 1,007	$ 794	$ 834