Condensed Consolidated Statements of Income (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Revenues
Revenues from rental properties	$ 237,837	$ 218,622
Management and other fee income	9,041	8,393
Total revenues	246,878	227,015
Operating expenses
Rent	3,305	3,321
Real estate taxes	31,307	28,454
Operating and maintenance	29,672	25,669
General and administrative expenses	37,219	34,020
Provision for doubtful accounts	1,717	1,832
Impairment charges	6,893	3,229
Depreciation and amortization	61,231	58,976
Total operating expenses	168,283	152,670
Operating income	78,595	74,345
Other income/(expense)
Mortgage financing income	1,699	986
Interest, dividends and other investment income	50	2,641
Other expense, net	(2,218)	(3,002)
Interest expense	(50,636)	(53,497)
Income from continuing operations before income taxes, equity in income of joint ventures, gain on change in control of interests and equity in income from other real estate investments	27,490	21,473
Provision for income taxes, net	(7,730)	(15,573)
Equity in income of equity method investments, net	53,261	24,111
Income from continuing operations	80,118	64,344
Gain on change in control of interests	3,744	23,170
Discontinued operations
Income from discontinued operating properties, net of tax	9,466	5,959
Impairment/loss on operating properties sold	(3,061)	(2,831)
Gain on disposition of operating properties	9,337	2,496
Income from discontinued operations	15,742	5,624
Gain on sale of operating properties, net of tax		540
Net income	95,860	70,508
Net income attributable to noncontrolling interests	(8,860)	(2,738)
Net income attributable to the Company	87,000	67,770
Preferred dividends	(14,573)	(14,573)
Net income available to the Company's common shareholders	72,427	53,197
Income from continuing operations:
-Basic (in Dollars per share)	$ 0.15	$ 0.12
-Diluted (in Dollars per share)	$ 0.15	$ 0.12
Net income attributable to the Company:
-Basic (in Dollars per share)	$ 0.18	$ 0.13
-Diluted (in Dollars per share)	$ 0.18	$ 0.13
Weighted average shares:
-Basic (in Shares)	408,367	406,662
-Diluted (in Shares)	409,444	407,666
Amounts attributable to the Company's common shareholders:
Income from continuing operations	63,256	47,872
Income from discontinued operations	9,171	5,325
Joint Ventures [Member]
Other income/(expense)
Equity in income of equity method investments, net	53,261	24,111
Other Real Estate Investments [Member]
Other income/(expense)
Equity in income of equity method investments, net	3,353	11,163
Continuing Operations [Member]
Operating expenses
Impairment charges	$ 3,832	$ 398