Segment Information - Summary of Information about Company's Reportable Operating Segments (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Segment Reporting Information [Line Items]
Lease revenue and other property revenue	$ 129,701	$ 220,925	$ 542,242	$ 680,981
Revenue from contracts with customers	14,394	6,499	28,437	23,051
Total revenue from operations	144,095	227,424	570,679	704,032
Rental operation expenses	(39,597)	(62,544)	(169,185)	(202,536)
Net operating income	104,498	164,880	401,494	501,496
Impairment charges	(19,890)	(10,284)	(68,394)	(60,353)
Depreciation and amortization	(49,629)	(85,210)	(196,515)	(266,370)
Interest income	5,055	6,807	15,412	22,365
Other income (expense), net	(1,454)	(64,340)	(99,316)	(65,298)
Unallocated expenses	(42,432)	(69,012)	(161,879)	(217,493)
Hurricane property credit (loss) and impairment loss, net	157	(6,089)	(817)	(6,089)
Equity in net (loss) income of joint ventures	(2,920)	4,811	9,687	2,429
(Reserve) Adjustment of preferred equity interests, net	(2,201)	15,377	(4,537)	(60,623)
Loss from continuing operations	(8,816)	(43,060)	(104,865)	(149,936)
Total gross real estate assets	5,171,227	8,697,077	5,171,227	8,697,077
Notes receivable, net	19,670	19,591	19,670	19,591	$ 19,675
Operating Segments | Shopping Center
Segment Reporting Information [Line Items]
Lease revenue and other property revenue	127,903	220,910	540,415	680,938
Revenue from contracts with customers	14,394	6,499	28,437	23,051
Total revenue from operations	142,297	227,409	568,852	703,989
Rental operation expenses	(39,597)	(62,547)	(169,185)	(202,526)
Net operating income	102,700	164,862	399,667	501,463
Impairment charges	(19,890)	(10,284)	(68,394)	(60,353)
Depreciation and amortization	(49,629)	(85,210)	(196,515)	(266,370)
Hurricane property credit (loss) and impairment loss, net		(6,089)	(974)	(6,089)
Equity in net (loss) income of joint ventures	(2,920)	4,811	9,687	2,429
Total gross real estate assets	5,171,227	8,697,077	5,171,227	8,697,077
Operating Segments | Loan Investments
Segment Reporting Information [Line Items]
Lease revenue and other property revenue	14	15	43	43
Revenue from contracts with customers	0	0	0	0
Total revenue from operations	14	15	43	43
Rental operation expenses	0	3	0	(10)
Net operating income	14	18	43	33
Interest income	5,055	6,807	15,412	22,365
(Reserve) Adjustment of preferred equity interests, net	(2,201)	15,377	(4,537)	(60,623)
Notes receivable, net	223,748	346,888	223,748	346,888
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Lease revenue and other property revenue	1,784		1,784
Total revenue from operations	1,784		1,784
Net operating income	1,784		1,784
Other income (expense), net	(1,454)	(64,340)	(99,316)	(65,298)
Unallocated expenses	(42,432)	(69,012)	(161,879)	(217,493)
Hurricane property credit (loss) and impairment loss, net	157		157
Notes receivable, net	$ (204,078)	$ (327,297)	$ (204,078)	$ (327,297)