Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010
Cash flow from operating activities:
Net income	$ 131,931	$ 114,975
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	188,812	185,034
Loss on operating/development properties held for sale/sold/transferred		65
Impairment charges	16,676	12,781
Gain on sale of development properties		(2,130)
Gain on sale of operating properties	(8,722)	(4,145)
Equity in loss/income of joint ventures, net	(49,810)	(27,717)
Equity in income from other real estate investments, net	(35,123)	(36,802)
Distributions from joint ventures and other real estate investments	108,595	89,034
Cash retained from excess tax benefits	(69)	(7)
Change in accounts and notes receivable	(5,182)	(13,395)
Change in accounts payable and accrued expenses	32,826	56,698
Change in other operating assets and liabilities	(12,019)	(16,187)
Net cash flow provided by operating activities	367,915	358,204
Cash flow from investing activities:
Acquisition of and improvements to operating real estate	(169,350)	(105,112)
Acquisition of and improvements to real estate under development	(26,939)	(33,972)
Investment in marketable securities		(9,041)
Proceeds from sale/repayments of marketable securities	178,290	6,336
Investments and advances to real estate joint ventures	(90,747)	(114,882)
Reimbursements of advances to real estate joint ventures	44,894	75,289
Other real estate investments	(5,225)	(7,940)
Reimbursements of advances to other real estate investments	50,536	6,541
Investment in mortgage loans receivable		(2,738)
Collection of mortgage loans receivable	14,732	26,265
Other investments	(730)	(3,952)
Reimbursements of other investments	11,122	8,792
Proceeds from sale of operating properties	65,593	221,477
Proceeds from sale of development properties	7,373	7,028
Net cash flow provided by investing activities	79,549	74,091
Cash flow from financing activities:
Principal payments on debt, excluding normal amortization of rental property debt	(24,393)	(213,089)
Principal payments on rental property debt	(17,130)	(18,336)
Principal payments on construction loan financings	(409)	(30,256)
Proceeds from mortgage/construction loan financings	13,685	13,960
Borrowings under revolving unsecured credit facilities	186,969	41,853
Repayment of borrowings under unsecured revolving credit facilities	(173,643)	(32,447)
Proceeds from issuance of unsecured term loan/notes		449,720
Repayment of unsecured term loan/notes	(88,000)	(471,725)
Financing origination costs	(855)	(5,012)
Redemption of non-controlling interests	(23,890)	(71,837)
Dividends paid	(265,674)	(230,192)
Cash retained from excess tax benefits	69	7
Proceeds from issuance of stock	4,832	171,117
Repurchase of common stock	(3,981)
Net cash flow used for financing activities	(392,420)	(396,237)
Change in cash and cash equivalents	55,044	36,058
Cash and cash equivalents, beginning of period	125,154	122,058
Cash and cash equivalents, end of period	180,198	158,116
Interest paid during the period (net of capitalized interest of $6,142, and $11,758, respectively)	145,378	168,102
Income taxes paid during the period	$ 2,062	$ 1,029