SEGMENTS (Summary of Segment Operating Results) (Details) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019 USD ($) ft²	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($) ft² segment location	Jun. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)
Segments reporting
Number of reportable segments | segment			4
Total revenues	$ 431,316	$ 181,005	$ 785,206	$ 342,684
Total operating expenses	(408,061)	(189,566)	(708,375)	(348,706)
Depreciation and amortization	(38,918)	(29,087)	(75,049)	(57,275)
Interest (expense) income, net	0		200		$ 200
Other (income) loss, net	10,288	266	10,461	266
Equity in (earnings) loss from real estate and other affiliates	6,354	16,299	16,305	30,685
Loss on sale or disposal of real estate	(144)	0	(150)	0
Segment EBT	17,801	(8,296)	60,742	(5,904)
Net income (loss)	13,328	(5,879)	45,253	(4,045)
Net loss attributable to noncontrolling interests	149	791	45	431
Net income (loss) attributable to common stockholders	13,477	(5,088)	45,298	(3,614)
Operating Assets
Segments reporting
Total revenues	109,219	88,808	201,172	176,555
Master Planned Communities
Segments reporting
Total revenues	$ 12,891	4,500	$ 19,921	8,011
Seaport District
Segments reporting
Area of real estate property (in sqft) | ft²	450,000		450,000
Operating locations | location			2
Total revenues	$ 72,859	62,765	$ 123,755	118,530
Strategic Developments
Segments reporting
Total revenues	236,347	24,932	440,358	39,588
Operating Segments
Segments reporting
Total revenues	431,316	181,005	785,206	342,684
Total operating expenses	(331,802)	(119,744)	(563,964)	(213,685)
Segment operating income	99,514	61,261	221,242	128,999
Depreciation and amortization	(37,037)	(27,350)	(71,554)	(54,100)
Interest (expense) income, net	(10,465)	(4,083)	(20,183)	(6,854)
Other (income) loss, net	714	235	1,353	537
Equity in (earnings) loss from real estate and other affiliates	6,354	16,300	16,305	30,683
Loss on sale or disposal of real estate	(144)	0	(150)	0
Segment EBT	58,936	46,363	147,013	99,265
Operating Segments | Operating Assets
Segments reporting
Total revenues	109,219	88,808	201,172	176,555
Total operating expenses	(48,727)	(40,988)	(91,639)	(82,999)
Segment operating income	60,492	47,820	109,533	93,556
Depreciation and amortization	(28,938)	(24,198)	(56,046)	(47,558)
Interest (expense) income, net	(20,059)	(17,308)	(39,050)	(33,995)
Other (income) loss, net	1,088	71	1,123	164
Equity in (earnings) loss from real estate and other affiliates	45	(1,000)	2,754	1,583
Segment EBT	12,628	5,385	18,314	13,750
Operating Segments | Master Planned Communities
Segments reporting
Total revenues	72,859	62,765	123,755	118,530
Total operating expenses	(40,392)	(37,003)	(68,906)	(73,371)
Segment operating income	32,467	25,762	54,849	45,159
Depreciation and amortization	(86)	(86)	(246)	(167)
Interest (expense) income, net	8,283	6,808	15,826	13,200
Other (income) loss, net	72	0	67	0
Equity in (earnings) loss from real estate and other affiliates	6,499	14,100	14,336	25,228
Segment EBT	47,235	46,584	84,832	83,420
Operating Segments | Seaport District
Segments reporting
Total revenues	12,891	4,500	19,921	8,011
Total operating expenses	(17,972)	(6,441)	(32,405)	(9,976)
Segment operating income	(5,081)	(1,941)	(12,484)	(1,965)
Depreciation and amortization	(6,753)	(1,953)	(12,946)	(4,197)
Interest (expense) income, net	(1,924)	3,278	(3,456)	6,995
Other (income) loss, net	(61)	0	(147)	0
Equity in (earnings) loss from real estate and other affiliates	(451)	(240)	(1,083)	(240)
Loss on sale or disposal of real estate	0	0	(6)	0
Segment EBT	(14,270)	(856)	(30,122)	593
Operating Segments | Strategic Developments
Segments reporting
Total revenues	236,347	24,932	440,358	39,588
Total operating expenses	(224,711)	(35,312)	(371,014)	(47,339)
Segment operating income	11,636	(10,380)	69,344	(7,751)
Depreciation and amortization	(1,260)	(1,113)	(2,316)	(2,178)
Interest (expense) income, net	3,235	3,139	6,497	6,946
Other (income) loss, net	(385)	164	310	373
Equity in (earnings) loss from real estate and other affiliates	261	3,440	298	4,112
Loss on sale or disposal of real estate	(144)	0	(144)	0
Segment EBT	13,343	(4,750)	73,989	1,502
Corporate expenses and other items
Segments reporting
Corporate expenses and other items	$ 45,608	$ 52,242	$ 101,760	$ 103,310
Tin Building | Seaport District
Segments reporting
Area of real estate property (in sqft) | ft²	53,000		53,000