Summary of Significant Accounting Policies - Disaggregated revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Disaggregation of Revenue [Line Items]
Total revenue	$ 92,172	$ 77,246	$ 183,176	$ 149,541
Franchise sales and other revenue
Disaggregation of Revenue [Line Items]
Total revenue	6,802	5,927	17,451	14,078
Real Estate
Disaggregation of Revenue [Line Items]
Total revenue	65,776	56,291	130,513	107,445
Real Estate | Fee revenue
Disaggregation of Revenue [Line Items]
Total revenue	59,952	51,361	115,077	95,595
Real Estate | Franchise sales and other revenue
Disaggregation of Revenue [Line Items]
Total revenue	5,824	4,930	15,436	11,850
Marketing Funds
Disaggregation of Revenue [Line Items]
Total revenue	22,909	18,042	45,760	36,187
Mortgage
Disaggregation of Revenue [Line Items]
Total revenue	3,115	2,410	6,143	4,733
Mortgage | Franchise sales and other revenue
Disaggregation of Revenue [Line Items]
Total revenue	606	494	1,255	1,052
Other.
Disaggregation of Revenue [Line Items]
Total revenue	372	503	760	1,176
U.S. | Company -Owned Regions | Fee revenue
Disaggregation of Revenue [Line Items]
Total revenue	42,733	37,613	81,887	70,159
U.S. | Independent Regions | Fee revenue
Disaggregation of Revenue [Line Items]
Total revenue	1,877	3,730	3,578	7,018
U.S. | Marketing Funds
Disaggregation of Revenue [Line Items]
Total revenue	17,641	16,359	35,200	32,541
Canada | Company -Owned Regions | Fee revenue
Disaggregation of Revenue [Line Items]
Total revenue	11,434	4,800	21,909	8,354
Canada | Independent Regions | Fee revenue
Disaggregation of Revenue [Line Items]
Total revenue	715	2,364	1,418	4,569
Canada | Marketing Funds
Disaggregation of Revenue [Line Items]
Total revenue	4,988	1,424	10,001	3,161
Global | Global. | Fee revenue
Disaggregation of Revenue [Line Items]
Total revenue	3,193	2,854	6,285	5,495
Global | Marketing Funds
Disaggregation of Revenue [Line Items]
Total revenue	$ 280	$ 259	$ 559	$ 485