Segments (Summary of Segment Operating Results) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Segments reporting
Total revenues	$ 212,457	$ 156,173	$ 403,037	$ 331,348
Depreciation and amortization	(49,788)	(46,963)	(99,096)	(108,600)
Other income (loss), net	(663)	1,607	(10,971)	(2,077)
Equity in earnings (losses) from real estate and other affiliates	7,867	(8,552)	23,663	2,797
Gain (loss) on sale or disposal of real estate and other assets, net	21,333	8,000	21,333	46,124
Gain (loss) on extinguishment of debt	(51)	0	(35,966)	0
Provision for impairment	(13,068)	0	(13,068)	(48,738)
Income (loss) before taxes	2,067	(40,947)	(87,297)	(200,129)
Net income (loss)	3,617	(34,103)	(64,542)	(159,185)
Net (income) loss attributable to noncontrolling interests	1,224	19	2,789	(33)
Net income (loss) attributable to common stockholders, basic	4,841	(34,084)	(61,753)	(159,218)
Operating segments
Segments reporting
Total revenues	212,364	156,086	402,843	331,243
Total operating expenses	(121,732)	(95,173)	(264,362)	(289,745)
Segment operating income (loss)	90,632	60,913	138,481	41,498
Depreciation and amortization	(48,674)	(45,512)	(96,830)	(105,328)
Interest income (expense), net	(6,691)	(18,369)	(13,731)	(39,130)
Other income (loss), net	(760)	1,485	(11,194)	(2,317)
Equity in earnings (losses) from real estate and other affiliates	7,867	(8,552)	23,663	2,797
Gain (loss) on sale or disposal of real estate and other assets, net	21,333	8,000	21,333	46,124
Gain (loss) on extinguishment of debt	(46)		(882)
Provision for impairment	(13,068)		(13,068)	(48,738)
Income (loss) before taxes	50,593	(2,035)	47,772	(105,094)
Corporate
Segments reporting
Corporate income, expenses and other items	(46,976)	(32,068)	(112,314)	(54,091)
Operating Assets
Segments reporting
Total revenues	113,422	84,277	209,861	198,534
Operating Assets | Operating segments
Segments reporting
Total revenues	113,422	84,277	209,861	198,534
Total operating expenses	(53,191)	(42,222)	(100,425)	(94,462)
Segment operating income (loss)	60,231	42,055	109,436	104,072
Depreciation and amortization	(39,975)	(36,995)	(79,626)	(74,084)
Interest income (expense), net	(18,152)	(23,103)	(37,152)	(49,296)
Other income (loss), net	(156)	226	(10,254)	167
Equity in earnings (losses) from real estate and other affiliates	(10,419)	475	(21,823)	4,869
Gain (loss) on sale or disposal of real estate and other assets, net	0	0	0	38,124
Gain (loss) on extinguishment of debt	(46)		(882)
Provision for impairment	0		0	(48,738)
Income (loss) before taxes	(8,517)	(17,342)	(40,301)	(24,886)
Operating Assets | Operating segments | Hospitality Revenue
Segments reporting
Total revenues	13,900	2,500	21,600	19,800
Total operating expenses	(11,000)	(4,400)	(18,900)	(17,200)
MPC Segment
Segments reporting
Total revenues	74,578	68,913	122,865	119,359
MPC Segment | Operating segments
Segments reporting
Total revenues	74,578	68,913	122,865	119,359
Total operating expenses	(33,905)	(31,970)	(57,172)	(55,692)
Segment operating income (loss)	40,673	36,943	65,693	63,667
Depreciation and amortization	(98)	(91)	(170)	(182)
Interest income (expense), net	10,615	8,303	21,372	16,857
Other income (loss), net	0	0	0	0
Equity in earnings (losses) from real estate and other affiliates	18,641	(2,968)	46,291	5,966
Gain (loss) on sale or disposal of real estate and other assets, net	0	0	0	0
Gain (loss) on extinguishment of debt	0		0
Provision for impairment	0		0	0
Income (loss) before taxes	69,831	42,187	133,186	86,308
Seaport Segment
Segments reporting
Total revenues	10,898	2,272	18,351	11,966
Seaport Segment | Operating segments
Segments reporting
Total revenues	10,898	2,272	18,351	11,966
Total operating expenses	(15,996)	(8,464)	(28,502)	(22,775)
Segment operating income (loss)	(5,098)	(6,192)	(10,151)	(10,809)
Depreciation and amortization	(7,004)	(6,776)	(13,839)	(27,651)
Interest income (expense), net	187	(4,626)	289	(9,679)
Other income (loss), net	(618)	(409)	(954)	(3,777)
Equity in earnings (losses) from real estate and other affiliates	(336)	(6,633)	(688)	(8,676)
Gain (loss) on sale or disposal of real estate and other assets, net	0	0	0	0
Gain (loss) on extinguishment of debt	0		0
Provision for impairment	0		0	0
Income (loss) before taxes	(12,869)	(24,636)	(25,343)	(60,592)
Strategic Developments Segment
Segments reporting
Total revenues	13,466	624	51,766	1,384
Strategic Developments Segment | Operating segments
Segments reporting
Total revenues	13,466	624	51,766	1,384
Total operating expenses	(18,640)	(12,517)	(78,263)	(116,816)
Segment operating income (loss)	(5,174)	(11,893)	(26,497)	(115,432)
Depreciation and amortization	(1,597)	(1,650)	(3,195)	(3,411)
Interest income (expense), net	659	1,057	1,760	2,988
Other income (loss), net	14	1,668	14	1,293
Equity in earnings (losses) from real estate and other affiliates	(19)	574	(117)	638
Gain (loss) on sale or disposal of real estate and other assets, net	21,333	8,000	21,333	8,000
Gain (loss) on extinguishment of debt	0		0
Provision for impairment	(13,068)		(13,068)	0
Income (loss) before taxes	$ 2,148	$ (2,244)	$ (19,770)	$ (105,924)