Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Operating Activities
Net income	$ 677,122	$ 319,156	$ 71,665
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	292,311	240,445	235,200
Equity in net income from unconsolidated joint ventures	(1,583)	(39,607)	(62,878)
Distributions of cumulative earnings from unconsolidated joint ventures	11,185	27,472	40,677
Equity in net gain on sale of interest in unconsolidated joint venture interest/ real estate	(2,918)	(128,921)	(6,691)
Purchase price fair value adjustment	(498,195)
Depreciable real estate reserves	5,789	2,750
(Gain) loss on sale of discontinued operations	(46,085)	(35,485)	6,841
Gain on sale of debt securities	(19,840)
Loan loss and other investment reserves, net of recoveries	6,722	17,751	150,510
(Gain) loss on investments in marketable securities	(4,866)	(490)	396
(Gain) loss on early extinguishment of debt	(904)	1,900	(86,006)
Deferred rents receivable	(87,230)	(47,223)	(26,267)
Other non-cash adjustments	2,385	(749)	(2,534)
Changes in operating assets and liabilities:
Restricted cash - operations	(681)	4,513	16,219
Tenant and other receivables	(4,720)	271	11,026
Related party receivables	2,461	2,398	(894)
Deferred lease costs	(38,412)	(42,035)	(21,202)
Other assets	4,029	4,860	(28,863)
Accounts payable, accrued expenses and other liabilities	10,704	(3,706)	(14,761)
Deferred revenue and land leases payable	5,586	(2,242)	(7,227)
Net cash provided by operating activities	312,860	321,058	275,211
Investing Activities
Acquisitions of real estate property	(446,756)	(270,614)	(16,059)
Additions to land, buildings and improvements	(159,100)	(108,145)	(90,971)
Escrowed cash - capital improvements/acquisition deposits	29,281	(40,215)	(5,318)
Investments in unconsolidated joint ventures	(109,920)	(87,844)	(107,716)
Distributions in excess of cumulative earnings from unconsolidated joint ventures	112,359	52,920	38,846
Net proceeds from disposition of real estate/joint venture interest	160,548	623,121	27,946
Other investments	12,186	32,607	(47,719)
Debt and preferred equity and other investments, net of repayments/participations	(338,195)	(183,015)	(144,388)
Net cash (used in) provided by investing activities	(739,597)	18,815	(345,379)
Financing Activities
Proceeds from mortgages and other loans payable	826,000	168,360	192,399
Repayments of mortgages and other loans payable	(765,378)	(149,832)	(169,688)
Proceeds from revolving credit facility and senior unsecured notes	1,901,068	670,992	30,433
Repayments of revolving credit facility and senior unsecured notes	(2,043,144)	(1,046,626)	(646,317)
Proceeds from stock options exercised and DRIP issuance	10,211	14,535	619
Net proceeds from sale of common stock	516,168		387,138
Net proceeds from sale of preferred stock		122,041
Purchases of treasury stock	(5,486)
Distributions to noncontrolling interests in other partnerships	(143,578)	(13,489)	(19,617)
Contributions from noncontrolling interests in other partnerships		2,788
Redemption of noncontrolling interests in operating partnership		(13,012)
Distributions to noncontrolling interests in operating partnership	(727)	(511)	(2,170)
Dividends paid on common and preferred stock	(63,866)	(58,984)	(78,321)
Other obligations related to mortgage loan participations	35,850
Deferred loan costs and capitalized lease obligation	(35,019)	(47,020)	(7,482)
Net cash provided by (used in) financing activities	232,099	(350,758)	(313,006)
Net decrease in cash and cash equivalents	(194,638)	(10,885)	(383,174)
Cash and cash equivalents at beginning of period	332,830	343,715	726,889
Cash and cash equivalents at end of period	138,192	332,830	343,715
Supplemental cash flow disclosures
Interest paid	275,106	222,904	257,393
Income taxes paid	$ 138	$ 1,041	$ 818