Condensed Consolidated Statements of Income (Unaudited) (USD $) In Thousands, except Per Share data	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Revenues from rental property	$ 219,236	$ 208,322	$ 441,038	$ 419,613
Rental property expenses:
Rent	(3,808)	(3,543)	(7,104)	(7,110)
Real estate taxes	(29,145)	(30,265)	(59,625)	(58,764)
Operating and maintenance	(28,279)	(27,514)	(62,260)	(59,082)
Impairment of property carrying values	(598)	(1,900)	(1,076)	(1,900)
Mortgage and other financing income	1,940	2,371	3,769	5,041
Management and other fee income	8,437	11,417	18,100	21,261
Depreciation and amortization	(61,521)	(57,808)	(126,946)	(113,501)
General and administrative expenses	(29,634)	(26,425)	(59,389)	(54,559)
Interest, dividends and other investment income	8,932	5,177	13,797	11,264
Other income/(expense), net	742	(1,109)	437	(1,424)
Interest expense	(55,804)	(58,167)	(111,361)	(113,702)
Income from other real estate investments	447	424	612	1,468
Gain on sale of development properties				1,793
Impairments:
Investments in other real estate investments		(2,112)		(5,994)
Marketable securities and other investments				(506)
Investments in real estate joint ventures	(3,123)		(3,123)
Income from continuing operations before income taxes, equity in income/(loss) of joint ventures and equity in income from other real estate investments	27,822	18,868	46,869	43,898
(Provision)/benefit for income taxes, net	(5,588)	101	(9,782)	(1,017)
Income from continuing operations	44,889	26,407	77,591	79,326
Discontinued operations:
(Loss)/income from discontinued operating properties, net of tax	(2,161)	1,103	(290)	3,706
Impairment/loss on operating/development properties held for sale/sold	(5,438)	(2,618)	(8,153)	(3,422)
Gain on disposition of operating properties	4,025		4,188
(Loss)/income from discontinued operations	(3,574)	(1,515)	(4,255)	284
Loss on transfer of operating properties, net		(57)		(57)
Gain on sale of operating properties, net		2,442		2,434
Total net gain on transfer or sale of operating properties		2,385		2,377
Net income	41,315	27,277	73,336	81,987
Net income attributable to noncontrolling interests	(2,606)	(2,666)	(5,665)	(6,540)
Net income attributable to the Company	38,709	24,611	67,671	75,447
Preferred stock dividends	(14,841)	(11,822)	(29,681)	(23,644)
Net income available to the Company's common shareholders	23,868	12,789	37,990	51,803
Income from continuing operations:
-Basic (in Dollars per share)	$ 0.07	$ 0.04	$ 0.10	$ 0.13
-Diluted (in Dollars per share)	$ 0.07	$ 0.04	$ 0.10	$ 0.13
Net income:
-Basic (in Dollars per share)	$ 0.06	$ 0.03	$ 0.09	$ 0.13
-Diluted (in Dollars per share)	$ 0.06	$ 0.03	$ 0.09	$ 0.13
Weighted average shares:
-Basic (in Shares)	406,559	405,705	406,500	405,635
-Diluted (in Shares)	407,562	406,009	407,472	405,871
Amounts available to the Company's common shareholders:
Income from continuing operations, net of tax	27,483	14,397	42,303	51,627
(Loss)/income from discontinued operations	(3,615)	(1,608)	(4,313)	176
Net income	23,868	12,789	37,990	51,803
Equity InIncome OfJoint Ventures Net [Member]
Impairments:
Equity in income of investment	17,824	(300)	30,169	14,619
Equity InIncome From Other Real Estate Investments Net [Member]
Impairments:
Equity in income of investment	$ 4,831	$ 7,738	$ 10,335	$ 21,826