Segment Information - Company's Reportable Segments (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Segment Reporting Information [Line Items]
Total revenues	$ 257,135	$ 245,355	$ 773,283	$ 728,907
Rental operation expenses	(73,348)	(71,385)	(223,529)	(211,024)
Net operating income (loss)	183,787	173,970	549,754	517,883
Impairment charges	0	(1,448)	(279,021)	(18,119)
Depreciation and amortization	(97,155)	(97,270)	(299,470)	(296,093)
Interest income	7,331	2,652	21,703	8,938
Other income (expense), net	(240)	(2,758)	(1,300)	(11,041)
Unallocated expenses	(76,341)	(76,100)	(243,987)	(236,097)
Equity in net income of joint ventures	648	3,620	2,351	10,241
Impairment of joint venture investments	0	0	0	(9,100)
Income (loss) from continuing operations	18,030	6,650	(242,198)	54,426
Gain on sale and change in control of interests, net	0	3,984	7,772	87,814
Total gross real estate assets	10,155,375	10,496,860	10,155,375	10,496,860
Notes receivable, net	47,430	57,645	47,430	57,645	$ 56,245
Operating Segments [Member] | Shopping Center [Member]
Segment Reporting Information [Line Items]
Total revenues	257,109	245,319	773,162	728,743
Rental operation expenses	(73,280)	(71,385)	(223,425)	(210,973)
Net operating income (loss)	183,829	173,934	549,737	517,770
Impairment charges		(1,448)	(279,021)	(18,119)
Depreciation and amortization	(97,155)	(97,270)	(299,470)	(296,093)
Equity in net income of joint ventures	648	3,620	2,351	9,755
Impairment of joint venture investments				(9,100)
Gain on sale and change in control of interests, net		3,984	7,772	87,814
Total gross real estate assets	10,155,375	10,496,860	10,155,375	10,496,860
Operating Segments [Member] | Loan Investments [Member]
Segment Reporting Information [Line Items]
Total revenues	26	36	121	164
Rental operation expenses	(68)	0	(104)	(51)
Net operating income (loss)	(42)	36	17	113
Interest income	7,331	2,652	21,703	8,938
Notes receivable, net	357,648	91,455	357,648	91,455
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Other income (expense), net	(240)	(2,758)	(1,300)	(11,041)
Unallocated expenses	(76,341)	(76,100)	(243,987)	(236,097)
Equity in net income of joint ventures				486
Notes receivable, net	$ (310,218)	$ (33,810)	$ (310,218)	$ (33,810)