REAL ESTATE AND OTHER AFFILIATES (Summary of Investments in Real Estate and Other Affiliates) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Investment in Real Estate and Other Affiliates
Carrying Value	$ 127,293		$ 121,757
Share of Earnings/Dividends	11,349	$ 9,951
Other equity investments (c)
Investment in Real Estate and Other Affiliates
Carrying Value	3,953		3,953
Share of Earnings/Dividends	3,724	3,625
Accounts payable and accrued expenses | The Metropolitan Downtown Columbia
Investment in Real Estate and Other Affiliates
Investment deficit position	$ 4,900		$ 4,700
Operating Assets | The Metropolitan Downtown Columbia | Equity Method Investments
Investment in Real Estate and Other Affiliates
Economic/Legal Ownership	50.00%		50.00%
Carrying Value	$ 0		$ 0
Share of Earnings/Dividends	$ 227	183
Operating Assets | Stewart Title of Montgomery County, TX | Equity Method Investments
Investment in Real Estate and Other Affiliates
Economic/Legal Ownership	50.00%		50.00%
Carrying Value	$ 3,767		$ 4,175
Share of Earnings/Dividends	$ 343	102
Operating Assets | Woodlands Sarofim 1 | Equity Method Investments
Investment in Real Estate and Other Affiliates
Economic/Legal Ownership	20.00%		20.00%
Carrying Value	$ 3,019		$ 2,985
Share of Earnings/Dividends	$ 35	20
Operating Assets | m.flats/TEN.M | Equity Method Investments
Investment in Real Estate and Other Affiliates
Economic/Legal Ownership	50.00%		50.00%
Carrying Value	$ 1,784		$ 2,431
Share of Earnings/Dividends	$ 65	(1,221)
Master Planned Communities | The Summit | Equity Method Investments
Investment in Real Estate and Other Affiliates
Economic/Legal Ownership	0.00%		0.00%
Carrying Value	$ 92,216		$ 84,455
Share of Earnings/Dividends	$ 8,934	7,837
Seaport District revenues | Mr. C Seaport | Equity Method Investments
Investment in Real Estate and Other Affiliates
Economic/Legal Ownership	35.00%		35.00%
Carrying Value	$ 7,000		$ 7,650
Share of Earnings/Dividends	$ (651)	(632)
Seaport District revenues | Bar Wayo (Momofuku) | Equity Method Investments
Investment in Real Estate and Other Affiliates
Economic/Legal Ownership	0.00%		0.00%
Carrying Value	$ 6,745		$ 7,469
Share of Earnings/Dividends	(1,392)	0
Strategic Developments | Equity Method Investments
Investment in Real Estate and Other Affiliates
Carrying Value	123,340		$ 117,804
Share of Earnings/Dividends	$ 7,625	6,326
Strategic Developments | Circle T Ranch and Power Center | Equity Method Investments
Investment in Real Estate and Other Affiliates
Economic/Legal Ownership	50.00%		50.00%
Carrying Value	$ 8,405		$ 8,207
Share of Earnings/Dividends	$ 86	35
Strategic Developments | HHMK Development | Equity Method Investments
Investment in Real Estate and Other Affiliates
Economic/Legal Ownership	50.00%		50.00%
Carrying Value	$ 10		$ 10
Share of Earnings/Dividends	$ 0	0
Strategic Developments | KR Holdings | Equity Method Investments
Investment in Real Estate and Other Affiliates
Economic/Legal Ownership	50.00%		50.00%
Carrying Value	$ 394		$ 422
Share of Earnings/Dividends	$ (22)	$ 2