Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010
Cash flows from operating activities:
Net Income	$ 39,648	$ 42,154
Adjustments to reconcile net income to net cash provided by operating activities:
Gain on sale of real estate	(5,051)	0
Gain on sale of marketable securities	(4,543)	(9,041)
Loss on early retirement of debt	820	10
Equity loss in co-investments excluding gain on sales of real estate	7,010	1,027
Gain on sales of co-investments	(919)	0
Amortization of discount on exchangeable bonds	0	58
Amortization of discount on marketable securities	(3,492)	(2,853)
Amortization of deferred interest from settlement of swaps	6,517	0
Amortization of discount on notes receivables	(1,316)	(3,435)
Depreciation	112,678	93,385
Amortization of deferred financing costs	2,201	2,437
Stock-based compensation	1,618	2,360
Prepaid expenses and other assets	(1,720)	1,450
Accounts payable and accrued liabilities	18,205	19,018
Other liabilities	1,166	1,714
Net cash provided by used in Operating activities	172,822	148,284
Additions to real estate:
Acquisitions	(43,328)	(96,596)
Improvements to recent acquisitions	(14,768)	(2,266)
Redevelopment expenditures	(26,929)	(8,966)
Revenue generating capital expenditures	(4,706)	(788)
Non-revenue generating capital expenditures	(13,946)	(19,169)
Dispositions of real estate	15,972	0
Additions to real estate under development	(72,816)	(110,972)
Changes in restricted cash and refundable deposits	(1,165)	(3,046)
Purchases of marketable securities	(8,048)	(18,294)
Sales and maturities of marketable securities	27,997	65,889
Purchases of and advances under notes and other receivables	0	(21,026)
Collections of notes and other receivables	643	1,832
Contributions to co-investments	(121,450)	(78,513)
Distributions from co-investments	1,904	40,397
Net cash used in investing activities	(260,640)	(251,518)
Cash flows from financing activities:
Borrowings under mortgage notes payable, lines of credit and bonds	872,042	616,385
Repayment under mortgage notes payable, lines of credit and bonds	(891,734)	(487,152)
Additions to deferred charges	(4,464)	(1,832)
Retirement of exchangeable bonds	0	(1,842)
Settlement of forward-starting swaps	(2,395)	(16,667)
Net proceeds from stock options exercised	6,714	3,108
Net proceeds from issuance of Series H preferred stock	71,209	0
Redemption of Series F preferred stock	(25,000)	0
Retirement of Series B preferred units	(78,800)	0
Net proceeds from issuance of common stock	257,008	116,641
Equity related issuance costs	(765)	0
Contributions from noncontrolling interest	0	3,990
Distributions to noncontrolling interest	(13,295)	(19,694)
Redemptions of noncontrolling interest	(4,645)	(23,745)
Common and preferred stock dividends paid	(102,790)	(91,950)
Net cash provided by financing activities	83,085	97,242
Net decrease in cash and cash equivalents	(4,733)	(5,992)
Cash and cash equivalents at beginning of period	13,753	20,660
Cash and cash equivalents at end of period	9,020	14,668
Supplemental disclosure of cash flow information:
Cash paid for interest, net of $6.9 million and $7.3 million capitalized in 2011 and 2010, respectively	66,629	61,595
Supplemental disclosure of noncash investing and financing activities:
Change in accrual of dividends	2,610	1,397
Change in value of derivative liabilities	1,760	24,945
Change in unrealized gain of marketable securities	2,283	3,208
Mortgage notes assumed in connection with purchase of real estate including the loan premiums recorded	20,927	87,540
Non-cash contribution from noncontrolling interest	800	0
Change in construction payable	1,566	714
Transfer of real estate under development to rental properties	86,995	0
Transfer of real estate under development to co-investments	$ 54,472	$ 0