REAL ESTATE AND OTHER AFFILIATES (Summary of Investments in Real Estate and Other Affiliates) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Investment in Real Estate and Other Affiliates
Carrying Value	$ 85,911		$ 76,593
Share of Earnings/Dividends	14,386	$ 8,520
Cost method investments
Investment in Real Estate and Other Affiliates
Carrying Value	3,855		3,952
Share of Earnings/Dividends	3,341	3,383
Accounts payable and accrued expenses | The Metropolitan Downtown Columbia
Investment in Real Estate and Other Affiliates
Investment deficit position	$ 3,100		$ 2,600
MPC | The Summit | Equity Method Investments
Investment in Real Estate and Other Affiliates
Economic/Legal Ownership	0.00%		0.00%
Carrying Value	$ 57,015		$ 45,886
Share of Earnings/Dividends	$ 11,128	5,280
Operating | Las Vegas 51s LLC | Equity Method Investments
Investment in Real Estate and Other Affiliates
Economic/Legal Ownership	100.00%		100.00%
Carrying Value	$ 0		$ 0
Share of Earnings/Dividends	$ 0	(152)
Operating | Constellation | Equity Method Investments
Investment in Real Estate and Other Affiliates
Economic/Legal Ownership	100.00%		100.00%
Carrying Value	$ 0		$ 0
Share of Earnings/Dividends	$ 0	64
Operating | 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	$ 80	57
Operating | 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	$ 3,579		$ 3,673
Share of Earnings/Dividends	$ 82	26
Operating | Woodlands Sarofim 1 | Equity Method Investments
Investment in Real Estate and Other Affiliates
Economic/Legal Ownership	20.00%		20.00%
Carrying Value	$ 2,697		$ 2,696
Share of Earnings/Dividends	$ 20	7
Operating | m.flats/TEN.M | Equity Method Investments
Investment in Real Estate and Other Affiliates
Economic/Legal Ownership	50.00%		50.00%
Carrying Value	$ 5,648		$ 6,521
Share of Earnings/Dividends	(937)	0
Strategic | Equity Method Investments
Investment in Real Estate and Other Affiliates
Carrying Value	82,056		$ 72,641
Share of Earnings/Dividends	$ 11,045	5,137
Strategic | 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	$ 4,456		$ 4,455
Share of Earnings/Dividends	$ 0	0
Strategic | 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 | KR Holdings | Equity Method Investments
Investment in Real Estate and Other Affiliates
Economic/Legal Ownership	50.00%		50.00%
Carrying Value	$ 0		$ 749
Share of Earnings/Dividends	$ 672	11
Strategic | 33 Peck Slip | Equity Method Investments
Investment in Real Estate and Other Affiliates
Economic/Legal Ownership	35.00%		35.00%
Carrying Value	$ 8,651		$ 8,651
Share of Earnings/Dividends	$ 0	$ (156)