Segment Information - Summary (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Segment Reporting Information [Line Items]
Revenues		$ 187,251	$ 206,878	$ 578,658	$ 641,676
Property operating expenses		(56,296)	(60,912)	(174,949)	(190,807)
Interest expense		(50,515)	(55,194)	(156,995)	(163,164)
Other expense		(7)	(38)	(41)	(377)
Gain on sales of real estate assets		8,056	7,880	13,811	15,998
Segment profit (loss)		88,489	98,614	260,484	303,326
Depreciation and amortization expense		(64,168)	(71,945)	(198,438)	(217,261)
General and administrative expense		(12,467)	(16,051)	(48,901)	(47,845)
Litigation settlement expense		22,688	0	(65,462)	0
Interest and other income		1,367	283	2,212	714
Gain on extinguishment of debt		0	0	71,722	0
Loss on impairment		(135,688)	(14,600)	(202,121)	(84,644)
Gain on investments/deconsolidation		11,174	0	11,174	387
Income tax benefit (provision)		(1,670)	(1,034)	(2,622)	1,846
Equity in earnings of unconsolidated affiliates		(1,759)	1,762	3,421	9,869
Net loss		(92,034)	(2,971)	(168,531)	(33,608)
Capital expenditures		36,491	41,183	97,603	115,656
Total Assets	[1]	4,769,918		4,769,918		$ 5,340,853
Malls
Segment Reporting Information [Line Items]
Revenues		171,514	188,440	526,354	585,097
Property operating expenses		(53,384)	(57,243)	(164,164)	(179,012)
Interest expense		(20,866)	(24,665)	(65,612)	(76,401)
Other expense		0	0	0	(84)
Gain on sales of real estate assets		3,292	92	5,770	92
Segment profit (loss)		100,556	106,624	302,348	329,692
Capital expenditures		34,961	38,512	94,545	105,593
Total Assets		4,351,303		4,351,303		4,868,141
All Other
Segment Reporting Information [Line Items]
Revenues		15,737	18,438	52,304	56,579
Property operating expenses		(2,912)	(3,669)	(10,785)	(11,795)
Interest expense		(29,649)	(30,529)	(91,383)	(86,763)
Other expense		(7)	(38)	(41)	(293)
Gain on sales of real estate assets		4,764	7,788	8,041	15,906
Segment profit (loss)		(12,067)	(8,010)	(41,864)	(26,366)
Capital expenditures		1,530	$ 2,671	3,058	$ 10,063
Total Assets		$ 418,615		$ 418,615		$ 472,712

[1] As of September 30, 2019, includes $484,345 of assets related to consolidated variable interest entities that can be used only to settle obligations of the consolidated variable interest entities and $346,999 of liabilities of consolidated variable interest entities for which creditors do not have recourse to the general credit of the Company. See Note 7.