Consolidated Statement of Capital (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2013
Increase (Decrease) in Stockholders' Equity
Balance		$ 7,120,010
Net income		60,455
Other comprehensive income	7,951	11,480
Preferred distributions		(14,406)
DRIP proceeds		26
Issuance of units		12,675
Amortization of deferred compensation plan		13,324
Redemption of preferred units		(192,500)
Preferred units issuance costs		(33)
Contributions - net proceeds from common stock offering		8,511
Contributions - treasury shares		6,090
Contributions - proceeds from stock options exercised		8,969
Contributions to consolidated joint venture		3,364
Distributions to noncontrolling interests		(8,152)
Cash distribution declared ($0.66 per common unit, none of which represented a return of capital for federal income tax purposes)		(62,674)
Balance	6,967,139	6,967,139
Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Stockholders' Equity
Balance		(30,649)
Other comprehensive income		11,480
Balance	(19,169)	(19,169)
Noncontrolling Interests
Increase (Decrease) in Stockholders' Equity
Balance		487,301
Net income		5,905
Contributions to consolidated joint venture		3,364
Distributions to noncontrolling interests		(8,152)
Balance	488,418	488,418
General Partner | Common Units
Increase (Decrease) in Stockholders' Equity
Balance		6,189,529
Balance (in units)		91,250,000
Net income		39,345
DRIP proceeds		26
Conversion of units		17,287
Conversion of units (in units)		224,000
Amortization of deferred compensation plan		13,324
Amortization of deferred compensation plan (in units)		4,000
Redemption of preferred units		(12,160)
Contributions - net proceeds from common stock offering		8,511
Contributions - net proceeds from common stock offering (in units)		95,000
Contributions - treasury shares		6,090
Contributions - treasury shares (in units)		83,000
Contributions - proceeds from stock options exercised		8,969
Contributions - proceeds from stock options exercised (in units)		157,000
Cash distribution declared ($0.66 per common unit, none of which represented a return of capital for federal income tax purposes)		(60,899)
Balance	6,210,022	6,210,022
Balance (in units)	91,813,000	91,813,000
Limited Partners | Common Units
Increase (Decrease) in Stockholders' Equity
Balance		71,524
Balance (in units)		2,760,000
Net income		799
Conversion of units		(17,287)
Conversion of units (in units)		(224,000)
Issuance of units		12,675
Issuance of units (in units)		258,000
Cash distribution declared ($0.66 per common unit, none of which represented a return of capital for federal income tax purposes)		(1,775)
Balance	65,936	65,936
Balance (in units)	2,794,000	2,794,000
Series C Preferred Units
Increase (Decrease) in Stockholders' Equity
Balance		180,340
Net income		6,932
Preferred distributions		(6,932)
Redemption of preferred units		(180,340)
Series I Preferred Units
Increase (Decrease) in Stockholders' Equity
Balance		221,965
Net income		7,474
Preferred distributions		(7,474)
Preferred units issuance costs		(33)
Balance	$ 221,932	$ 221,932