Condensed Consolidated Statements Of Equity (USD $)		Total	Preferred Shares Of Beneficial Interest [Member]	Common Shares Of Beneficial Interest [Member]	Additional Paid-In Capital [Member]	Net Income Less Than Accumulated Dividends [Member]	Accumulated Other Comprehensive Loss [Member]	Noncontrolling Interests [Member]
Balance at Dec. 31, 2012		$ 1,740,155,000	$ 7,000	$ 3,663,000	$ 1,934,183,000	$ (335,980,000)	$ (24,743,000)	$ 163,025,000
Increase (Decrease) in Equity [Roll Forward]
Net Income		148,995,000				109,786,000		39,209,000
Redemption of preferred shares		(275,000,000)	(5,000)		(257,051,000)	(17,944,000)
Shares issued under benefit plans		11,355,000		20,000	11,335,000
Dividends declared - common shares	[1]	(74,317,000)				(74,317,000)
Dividends declared - preferred shares	[2]	(12,322,000)				(12,322,000)
Distributions to noncontrolling interests		(8,241,000)						(8,241,000)
Contributions from noncontrolling interests		10,182,000						10,182,000
Other comprehensive income		9,079,000					9,079,000
Other, net		1,464,000			811,000	(431,000)		1,084,000
Balance at Jun. 30, 2013		1,551,350,000	2,000	3,683,000	1,689,278,000	(331,208,000)	(15,664,000)	205,259,000
Balance at Dec. 31, 2013		1,687,978,000	2,000	3,683,000	1,679,229,000	(300,537,000)	(4,202,000)	309,803,000
Increase (Decrease) in Equity [Roll Forward]
Net Income		101,765,000				98,699,000		3,066,000
Shares issued under benefit plans		7,322,000		8,000	7,314,000
Dividends declared - common shares	[1]	(79,427,000)				(79,427,000)
Dividends declared - preferred shares	[2]	(4,876,000)				(4,876,000)
Distributions to noncontrolling interests		(3,305,000)						(3,305,000)
Contributions from noncontrolling interests		980,000						980,000
Acquisition of noncontrolling interests		0			(11,015,000)			(11,015,000)
Disposition of noncontrolling interests		(144,263,000)						(144,263,000)
Other comprehensive income		1,290,000					1,290,000
Other, net		(451,000)			225,000	(544,000)		(132,000)
Balance at Jun. 30, 2014		$ 1,567,013,000	$ 2,000	$ 3,691,000	$ 1,697,783,000	$ (286,685,000)	$ (2,912,000)	$ 155,134,000

[1] Common dividend per share was $.65 and $.61 for the six months ended June 30, 2014 and 2013, respectively.

[2] Series D preferred dividend per share was $13.08 for the six months ended June 30, 2013. Series F preferred dividend per share was $81.25 and $78.99 for the six months ended June 30, 2014 and 2013, respectively.