SEGMENTS (Summary of Segment Operating Results) (Details) ft² in Thousands		12 Months Ended
	Aug. 18, 2020 USD ($)	Dec. 31, 2020 USD ($) ft² location segment	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Segments reporting
Number of operating segments | segment		4
Number of operating locations | location		2
Total revenues		$ 699,489,000	$ 1,300,539,000	$ 1,064,537,000
Depreciation and amortization		(217,467,000)	(155,798,000)	(126,565,000)
Other income (loss), net		130,000	12,179,000	(936,000)
Equity in earnings (losses) from real estate and other affiliates		271,099,000	30,629,000	39,954,000
Gain (loss) on sale or disposal of real estate and other assets, net		59,942,000	22,362,000	(4,000)
Selling profit from sales-type leases		0	13,537,000
Gain (loss) on extinguishment of debt	$ (13,200,000)	(13,169,000)	4,641,000	0
Provision for impairment		(48,738,000)	0	0
Income (loss) before income taxes		8,480,000	103,540,000	73,218,000
Net income (loss)		(3,173,000)	74,295,000	57,726,000
Net (income) loss attributable to noncontrolling interests		(22,981,000)	(339,000)	(714,000)
Net income (loss) attributable to common stockholders		(26,154,000)	73,956,000	57,012,000
Operating Assets Segment
Segments reporting
Total revenues		372,057,000	400,131,000	348,242,000
MPC Segment
Segments reporting
Total revenues		$ 283,953,000	386,781,000	309,451,000
Seaport District Segment
Segments reporting
Area of real estate property | ft²		453
Number of primary locations | location		3
Total revenues		$ 23,814,000	55,645,000	32,632,000
Strategic Developments Segment
Segments reporting
Total revenues		19,407,000	457,948,000	374,212,000
Operating Segments
Segments reporting
Total revenues		699,231,000	1,300,505,000	1,064,537,000
Total operating expenses		(495,349,000)	(840,514,000)	(668,484,000)
Operating income		203,882,000	459,991,000	396,053,000
Depreciation and amortization		(210,836,000)	(147,777,000)	(119,309,000)
Interest expense (income), net		(61,024,000)	(50,554,000)	(25,865,000)
Other income (loss), net		89,000	2,552,000	(3,972,000)
Equity in earnings (losses) from real estate and other affiliates		271,099,000	30,629,000	39,937,000
Gain (loss) on sale or disposal of real estate and other assets, net		59,942,000	27,113,000	(4,000)
Selling profit from sales-type leases		0	13,537,000
Gain (loss) on extinguishment of debt		(13,169,000)	4,851,000
Provision for impairment		(48,738,000)
Income (loss) before income taxes		201,245,000	340,342,000	286,840,000
Operating Segments | Operating Assets Segment
Segments reporting
Total revenues		372,057,000	400,131,000	348,242,000
Total operating expenses		(185,480,000)	(187,322,000)	(164,445,000)
Operating income		186,577,000	212,809,000	183,797,000
Depreciation and amortization		(162,324,000)	(115,499,000)	(103,293,000)
Interest expense (income), net		(91,411,000)	(81,029,000)	(71,551,000)
Other income (loss), net		540,000	1,142,000	(7,107,000)
Equity in earnings (losses) from real estate and other affiliates		(7,366,000)	3,672,000	1,994,000
Gain (loss) on sale or disposal of real estate and other assets, net		38,232,000	0	(4,000)
Selling profit from sales-type leases		0	13,537,000
Gain (loss) on extinguishment of debt		(1,521,000)	0
Provision for impairment		(48,738,000)
Income (loss) before income taxes		(86,011,000)	34,632,000	3,836,000
Operating Segments | Operating Assets Segment | Hospitality revenues
Segments reporting
Total revenues		35,200,000	87,900,000	82,000,000.0
Total operating expenses		(32,300,000)	(60,200,000)	(59,200,000)
Operating Segments | MPC Segment
Segments reporting
Total revenues		283,953,000	386,781,000	309,451,000
Total operating expenses		(128,597,000)	(183,472,000)	(163,517,000)
Operating income		155,356,000	203,309,000	145,934,000
Depreciation and amortization		(365,000)	(424,000)	(243,000)
Interest expense (income), net		36,587,000	32,019,000	26,919,000
Other income (loss), net		0	601,000	18,000
Equity in earnings (losses) from real estate and other affiliates		17,845,000	28,336,000	36,284,000
Gain (loss) on sale or disposal of real estate and other assets, net		0	0	0
Selling profit from sales-type leases		0	0
Gain (loss) on extinguishment of debt		0	0
Provision for impairment		0
Income (loss) before income taxes		209,423,000	263,841,000	208,912,000
Operating Segments | Seaport District Segment
Segments reporting
Total revenues		23,814,000	55,645,000	32,632,000
Total operating expenses		(46,112,000)	(77,872,000)	(49,716,000)
Operating income		(22,298,000)	(22,227,000)	(17,084,000)
Depreciation and amortization		(41,602,000)	(26,381,000)	(12,466,000)
Interest expense (income), net		(12,512,000)	(12,865,000)	6,291,000
Other income (loss), net		(2,616,000)	(22,000)	102,000
Equity in earnings (losses) from real estate and other affiliates		(9,292,000)	(2,592,000)	(705,000)
Gain (loss) on sale or disposal of real estate and other assets, net		0	(6,000)	0
Selling profit from sales-type leases		0	0
Gain (loss) on extinguishment of debt		(11,648,000)	4,851,000
Provision for impairment		0
Income (loss) before income taxes		(99,968,000)	(59,242,000)	(23,862,000)
Operating Segments | Strategic Developments Segment
Segments reporting
Total revenues		19,407,000	457,948,000	374,212,000
Total operating expenses		(135,160,000)	(391,848,000)	(290,806,000)
Operating income		(115,753,000)	66,100,000	83,406,000
Depreciation and amortization		(6,545,000)	(5,473,000)	(3,307,000)
Interest expense (income), net		6,312,000	11,321,000	12,476,000
Other income (loss), net		2,165,000	831,000	3,015,000
Equity in earnings (losses) from real estate and other affiliates		269,912,000	1,213,000	2,364,000
Gain (loss) on sale or disposal of real estate and other assets, net		21,710,000	27,119,000	0
Selling profit from sales-type leases		0	0
Gain (loss) on extinguishment of debt		0	0
Provision for impairment		0
Income (loss) before income taxes		177,801,000	101,111,000	97,954,000
Corporate
Segments reporting
Corporate expenses and other items		$ (204,418,000)	$ (266,047,000)	$ (229,114,000)
Tin Building | Seaport District Segment
Segments reporting
Area of real estate property | ft²		53