Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Cash flows from operating activities:
Net income	$ 69,729	$ 28,560
Adjustments to reconcile net income to net cash provided by operating activities:
Gain on sale of marketable securities	(521)	(4,543)
Gain on remeasurement of co investment	(21,947)	0
Loss on early retirement of debt	1,450	253
Co-investments	3,770	2,120
Amortization expense	5,754	5,590
Amortization of discount on marketable securities	(2,518)	(2,297)
Amortization of discount on notes receivables	(917)	(878)
Gain on the sales of real estate	(10,870)	(5,853)
Depreciation	82,629	74,541
Equity-based compensation	1,925	1,056
Changes in operating assets and liabilities:
Prepaid expenses and other assets	(4,420)	(697)
Accounts payable and accrued liabilities	5,133	5,299
Other liabilities	195	1,200
Net cash provided by operating activities	129,392	104,351
Additions to real estate:
Acquisitions of real estate	(80,502)	(38,958)
Improvements to recent acquisitions	(3,569)	(11,804)
Redevelopment	(17,223)	(16,296)
Revenue generating capital expenditures	(1,638)	(1,220)
Non-revenue generating capital expenditures	(7,040)	(7,711)
Acquisition of and additions to real estate under development	(17,166)	(65,695)
Acquisition of membership interest in co-investment	(85,000)	0
Dispositions of real estate	27,800	15,972
Changes in restricted cash and refundable deposits	(1,805)	(3,210)
Purchases of marketable securities	(34,363)	(6,805)
Sales and maturities marketable securities	5,070	27,997
Collections of notes and other receivables	6,574	368
Contributions to co-investments	(114,746)	(43,207)
Distributions from co-investments	7,430	450
Net cash used in investing activities	(316,178)	(150,119)
Cash flows from financing activities:
Borrowings under debt agreements	762,580	645,419
Repayment of debt	(671,153)	(661,193)
Additions to deferred charges	(2,622)	(1,441)
Payments to settle derivative instruments	0	(2,395)
Net proceeds from issuance of Preferred stock, Series H	0	71,427
Retirement of Series B preferred units	0	(78,800)
Redemption of Series F preferred stock	0	(25,000)
Equity related issuance cost	(274)	(591)
Net proceeds from stock options exercised	1,400	5,983
Net proceeds from issuance of common stock	170,944	168,592
Contributions from noncontrolling interest	2,400	0
Distributions to noncontrolling interest	(9,134)	(9,667)
Redemption of noncontrolling interest	(681)	(4,019)
Common and preferred stock dividends paid	(75,431)	(67,491)
Net cash provided by financing activities	178,029	40,824
Net (decrease) increase in cash and cash equivalents	(8,757)	(4,944)
Cash and cash equivalents at beginning of year	12,889	13,753
Cash and cash equivalents at end of year	4,132	8,809
Supplemental disclosure of cash flow information:
Cash paid for interest, net of $3.9 million, and $4.5 million capitalized in 2012 and 2011, respectively	45,575	43,594
Supplemental disclosure of noncash investing and financing activities:
Transfer from real estate under development to rental properties	4,294	40,784
Transfer from real estate under development to co-investments	148,053	48,886
Mortgage notes assumed in connection with purchases of real estate including the loan premiums recorded	30,298	10,500
Contribution of note receivable to co-investment	12,325	0
Change in accrual of dividends	4,097	1,570
Change in fair value of derivative liabilities	2,841	1,836
Purchase of marketable securities pending settlement	8,340	0
Change in fair value of marketable securities	845	2,283
Change in construction payable	2,930	2,041
Non cash contribution from noncontrolling interest	$ 0	$ 800