Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Cash Flows from Operating Activities:
Net income	$ 575,886	$ 433,040
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization (including amortization of deferred financing costs)	420,494	423,959
Straight-lining of rental income	(108,529)	(56,983)
Net gain on disposition of wholly owned and partially owned assets	(104,897)	(13,205)
Return of capital from real estate fund investments	91,036	215,676
Reversal of allowance for deferred tax assets	(90,030)	0
Net gains on sale of real estate and other	(65,396)	(57,796)
Distributions of income from partially owned entities	51,650	42,164
Amortization of below-market leases, net	(45,918)	(32,663)
Net realized and unrealized gains on real estate fund investments	(38,781)	(131,558)
Other non-cash adjustments	35,190	28,691
Loss from partially owned entities	8,709	78,676
Impairment losses	256	20,842
Defeasance cost in connection with the refinancing of mortgage notes payable	0	5,589
Changes in operating assets and liabilities:
Real estate fund investments	(95,010)	(3,392)
Tenant and other receivables, net	1,892	(2,775)
Prepaid assets	(77,899)	(85,372)
Other assets	(92,413)	(68,833)
Accounts payable and accrued expenses	(5,799)	36,949
Other liabilities	(16,168)	(3,190)
Net cash provided by operating activities	443,525	828,569
Cash Flows from Investing Activities:
Acquisitions of real estate and other	(388,565)	(95,546)
Proceeds from sales of real estate and related investments	375,850	335,489
Development costs and construction in progress	(339,586)	(368,571)
Additions to real estate	(207,845)	(171,660)
Restricted cash	201,895	101,592
Investments in partially owned entities	(144,890)	(91,697)
Distributions of capital from partially owned entities	31,822	8,130
Investments in loans receivable	(25,845)	(11,380)
Proceeds from repayments of mortgage and mezzanine loans receivable and other	16,781	96,504
Net cash used in investing activities	(480,383)	(197,139)
Cash Flows from Financing Activities:
Proceeds from borrowings	2,876,460	1,713,285
Repayments of borrowings	(2,539,677)	(343,354)
Dividends paid on common shares	(355,945)	(410,724)
Cash included in the spin-off of Urban Edge Properties	(225,000)	0
Distributions to noncontrolling interests	(93,738)	(208,773)
Dividends paid on preferred shares	(60,213)	(61,102)
Contributions from noncontrolling interests	51,725	5,297
Debt issuance costs	(37,467)	(40,424)
Proceeds received from exercise of employee share options	15,273	13,738
Repurchase of shares related to stock compensation agreements and/or related tax withholdings and other	(4,900)	(637)
Purchase of marketable securities in connection with the defeasance of mortgage notes payable	0	(198,884)
Net Cash (used in) provided by financing activities	(373,482)	468,422
Net (decrease) increase in cash and cash equivalents	(410,340)	1,099,852
Cash and cash equivalents at beginning of period	1,198,477	583,290
Cash and cash equivalents at end of period	788,137	1,683,142
Supplemental Disclosure Of Cash Flow Information:
Cash payments for interest, excluding capitalized interest of $40,924 and $46,517	256,254	317,162
Cash payments for income taxes	7,640	9,407
Non-cash distribution of Urban Edge Properties:
Assets	1,722,263	0
Liabilities	(1,482,660)	0
Equity	(239,603)	0
Adjustments to carry redeemable Class A units at redemption value	295,713	(144,231)
Transfer of interest in real estate to Pennsylvania Real Estate Investment Trust	(145,313)	0
Write-off of fully depreciated assets	(127,788)	(103,184)
Accrued capital expenditures included in accounts payable and accrued expenses	95,535	103,032
Class A units in connection with acquisition	80,000	0
Financing assumed in acquisitions	62,000	0
Marketable securities transferred in connection with the defeasance of mortgage notes payable	0	198,884
Defeasance of mortgage notes payable	0	(193,406)
Elimination of a mortgage and mezzanine loan asset and liability	0	59,375
Transfer of interest in real estate fund investments to an unconsolidated joint venture	0	(58,564)
Transfer of noncontrolling interest in real estate fund investments	0	(33,028)
Discontinued Operations [Member]
Adjustments to reconcile net income to net cash provided by operating activities:
Loss from partially owned entities	7,961	77,426
Acquisitions [Member]
Non-cash distribution of Urban Edge Properties:
Like-kind exchange of real estate	80,269	50,159
Dispositions [Member]
Non-cash distribution of Urban Edge Properties:
Like-kind exchange of real estate	$ (213,621)	$ (50,159)