SEGMENT INFORMATION (Financial Information) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Segment Reporting Information [Line Items]
Revenues	$ 1,214,513	$ 1,238,975	$ 3,298,056	$ 3,664,766
Consolidated Adjusted EBITDA	18,950	12,349	57,006	56,971
Depreciation and amortization expense	2,790	2,767	8,148	7,154
Stock compensation expense	11,764	5,800	29,912	22,828
Stock option expense	2,533	3,756	7,659	10,872
Operating profit	1,863	26	11,287	16,117
Goodwill	24,879		24,879		$ 27,212
Operating segments
Segment Reporting Information [Line Items]
Goodwill	24,879		24,879		27,212
Operating segments | North American Realty
Segment Reporting Information [Line Items]
Revenues	1,198,207	1,226,368	3,254,666	3,632,276
Consolidated Adjusted EBITDA	27,171	22,445	82,496	91,115
Goodwill	14,244		14,244		16,577
Operating segments | International Realty
Segment Reporting Information [Line Items]
Revenues	14,896	10,146	37,644	26,148
Consolidated Adjusted EBITDA	(2,647)	(4,614)	(10,105)	(9,584)
Operating segments | Virbela
Segment Reporting Information [Line Items]
Revenues	1,720	2,328	5,694	6,181
Consolidated Adjusted EBITDA	(1,297)	(3,197)	(3,789)	(8,684)
Goodwill	8,248		8,248		8,248
Operating segments | Other Affiliated Services
Segment Reporting Information [Line Items]
Revenues	979	1,417	3,729	3,298
Consolidated Adjusted EBITDA	(918)	(563)	(2,767)	(2,139)
Goodwill	2,387		2,387		$ 2,387
Operating segments | Corporate expenses and other
Segment Reporting Information [Line Items]
Consolidated Adjusted EBITDA	(3,359)	(1,722)	(8,829)	(13,737)
Segment eliminations
Segment Reporting Information [Line Items]
Revenues	$ (1,289)	$ (1,284)	$ (3,677)	$ (3,137)