INVESTMENT IN REAL ESTATE AND OTHER AFFILIATES (Narrative) (Details)				1 Months Ended	3 Months Ended	12 Months Ended
	Jun. 01, 2016 ft²	Mar. 16, 2016 ft²	Oct. 04, 2013 USD ($) a	Jan. 31, 2016 USD ($)	Mar. 31, 2015 USD ($) item	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Jun. 30, 2016 USD ($)
Real Estate and Other Affiliates
Revenues						$ 58,600,000
Net income						23,200,000
Gross margin						31,200,000
Area of land sold | ft²		42,694
Equity in earnings						25,498,000	$ 56,818,000	$ 3,721,000
Gain recognized on the sale of Redlands Promenade						125,000
Land						277,932,000	320,936,000
Land sales						248,595,000	215,318,000	$ 187,399,000
The Summit
Real Estate and Other Affiliates
Preferred return, on capital (as a percent)					5.00%
Entitlement of distribution by joint venture (in times) | item					2
Total assets						166,900,000	151,400,000
Total liabilities						118,900,000	116,600,000
Equity						48,000,000	34,800,000
Revenues							79,800,000
Net income							43,500,000
Gross margin							47,100,000
Circle T Ranch and Power Center
Real Estate and Other Affiliates
Area of land sold | ft²	72
Equity in earnings							10,500,000
m.flats/TEN.M
Real Estate and Other Affiliates
Fair value of the land contributed to joint venture			$ 4,000,000
Transaction value of the land contributed to joint venture			$ 23,400,000
Area of land contributed to the joint venture (in acres) | a			5
Additional capitalized development costs incurred resulting from contribution of land			$ 3,100,000
Total book value contribution			7,100,000
Transaction value, per constructed unit of land contributed to joint venture			$ 53,500,000,000
Distribution of the cash contributed by joint venture partner				$ 7,300,000
Contribution made till date							6,300,000
Gain recognized on the sale of Redlands Promenade							200,000
m.flats/TEN.M | Kettler Inc
Real Estate and Other Affiliates
Amount funded in cash to joint venture				16,100,000
m.flats/TEN.M | Construction Loan Payable
Real Estate and Other Affiliates
Non-recourse construction loan				$ 88,000,000
Option to extend, term				1 year
33 Peck Slip
Real Estate and Other Affiliates
Amount funded in cash to joint venture						700,000	2,300,000
Capital contribution				$ 6,000,000
Investment in joint venture						8,700,000
33 Peck Slip | Bridge Loan
Real Estate and Other Affiliates
Amount of bridge loan				$ 25,000,000
Interest rate margin (as a percent)				5.00%
33 Peck Slip | Construction Loan Payable
Real Estate and Other Affiliates
Redevelopment loan									$ 36,000,000
Equity Method Investments | The Summit
Real Estate and Other Affiliates
Fair value of the land contributed to joint venture					$ 13,400,000
SID Bonds transferred to a joint venture					1,300,000
Transaction value of the land contributed to joint venture					125,400,000
Value of land contributed to joint venture, price per acre					226,000
Equity Method Investments | The Summit | Maximum
Real Estate and Other Affiliates
Maximum capital contribution required					$ 30,000,000
Equity Method Investments | 33 Peck Slip
Real Estate and Other Affiliates
Equity in earnings						$ (643,000)	$ 106,000
One Month LIBOR
Real Estate and Other Affiliates
Interest rate margin (as a percent)						1.49%
One Month LIBOR | m.flats/TEN.M | Construction Loan Payable
Real Estate and Other Affiliates
Interest rate margin (as a percent)				2.40%