Consolidated Statements of Cash Flows (USD $)	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Operating Activities
Net income	$ 61,585,000	$ 153,614,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	173,028,000	162,028,000
Depreciable real estate reserves, net of recoveries	2,150,000	(5,789,000)
Equity in net income from unconsolidated joint ventures	(1,313,000)	(69,330,000)
Distributions of cumulative earnings from unconsolidated joint ventures	13,467,000	77,981,000
Purchase price fair value adjustment	2,305,000
Equity in net loss (gain) on sale of interest in unconsolidated joint venture/real estate	3,583,000	(16,794,000)
Gain on sale of discontinued operations	(1,113,000)	(6,627,000)
Loan loss and other investment reserves, net of recoveries		564,000
Loss on early extinguishment of debt	10,968,000
Deferred rents receivable	(29,452,000)	(37,318,000)
Other non-cash adjustments	(28,375,000)	3,759,000
Changes in operating assets and liabilities:
Restricted cash - operations	6,127,000	(7,104,000)
Tenant and other receivables	4,896,000	(5,006,000)
Related party receivables	768,000	(3,792,000)
Deferred lease costs	(19,106,000)	(28,549,000)
Other assets	4,075,000	(27,176,000)
Accounts payable, accrued expenses and other liabilities	1,793,000	9,609,000
Deferred revenue and land leases payable	8,102,000	(2,135,000)
Net cash provided by operating activities	213,488,000	197,935,000
Investing Activities
Acquisitions of real estate property	(52,534,000)	(248,468,000)
Additions to land, buildings and improvements	(61,531,000)	(76,585,000)
Escrowed cash - capital improvements/acquisition deposits	(394,000)	(65,030,000)
Investments in unconsolidated joint ventures	(81,913,000)	(131,820,000)
Distributions in excess of cumulative earnings from unconsolidated joint ventures	11,117,000	44,172,000
Net proceeds from disposition of real estate/joint venture interest	5,852,000	26,099,000
Other investments	(18,038,000)	(31,206,000)
Debt and preferred equity and other investments, net of repayments/participations	150,919,000	(75,209,000)
Net cash used in investing activities	(46,522,000)	(558,047,000)
Financing Activities
Proceeds from mortgages and other loans payable	980,333,000	1,113,500,000
Repayments of mortgages and other loans payable	(833,728,000)	(472,288,000)
Proceeds from credit facility and senior unsecured notes	370,000,000	468,339,000
Repayments of credit facility and senior unsecured notes	(404,970,000)	(840,793,000)
Proceeds from stock options exercised and DRIP issuance	8,995,000	105,195,000
Net proceeds from sale of common stock/preferred stock	8,478,000	201,307,000
Redemption of preferred stock	(192,500,000)
Purchases of treasury stock		(11,158,000)
Distributions to noncontrolling interests in other partnerships	(8,152,000)	(11,999,000)
Contributions from noncontrolling interests in other partnerships	3,364,000	18,799,000
Distributions to noncontrolling interests in the Operating Partnership	(1,775,000)	(1,561,000)
Dividends paid on common and preferred stock	(79,534,000)	(59,155,000)
Deferred loan costs and capitalized lease obligations	(8,492,000)	(31,467,000)
Net cash (used in) provided by financing activities	(157,981,000)	478,719,000
Net increase in cash and cash equivalents	8,985,000	118,607,000
Cash and cash equivalents at beginning of period	189,984,000	138,192,000
Cash and cash equivalents at end of period	$ 198,969,000	$ 256,799,000