Consolidated Statement of Capital (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013
Increase (Decrease) in Stockholders' Equity
Balance	$ 7,120,010
Net income	29,772
Other comprehensive income:	3,529
Preferred distributions	(7,407)
DRIP proceeds	13
Issuance of units	777
Amortization of deferred compensation plan	7,822
Preferred units issuance costs	(33)
Common units issuance costs	(24)
Contributions - proceeds from stock options exercised	4,533
Contributions to consolidated joint venture	3,110
Distributions to noncontrolling interests	(4,879)
Cash distribution declared ($0.33 per common unit, none of which represented a return of capital for federal income tax purposes)	(31,370)
Balance	7,125,853
Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Stockholders' Equity
Balance	(30,649)
Other comprehensive income:	3,529
Balance	(27,120)
Noncontrolling Interests
Increase (Decrease) in Stockholders' Equity
Balance	487,301
Net income	2,901
Contributions to consolidated joint venture	3,110
Distributions to noncontrolling interests	(4,879)
Balance	488,433
General Partner | Common Units
Increase (Decrease) in Stockholders' Equity
Balance	6,189,529
Balance (in units)	91,250,000
Net income	18,909
DRIP proceeds	13
Redemption of units	17,287
Redemption of units (in units)	224,000
Amortization of deferred compensation plan	7,822
Amortization of deferred compensation plan (in units)	2,000
Common units issuance costs	(24)
Contributions - proceeds from stock options exercised	4,533
Contributions - proceeds from stock options exercised (in units)	79,000
Cash distribution declared ($0.33 per common unit, none of which represented a return of capital for federal income tax purposes)	(30,517)
Balance	6,207,552
Balance (in units)	91,555,000
Limited Partners | Common Units
Increase (Decrease) in Stockholders' Equity
Balance	71,524
Balance (in units)	2,760,000
Net income	555
Redemption of units	(17,287)
Redemption of units (in units)	(224,000)
Issuance of units	777
Issuance of units (in units)	50,000
Cash distribution declared ($0.33 per common unit, none of which represented a return of capital for federal income tax purposes)	(853)
Balance	54,716
Balance (in units)	2,586,000
Series C Preferred Units
Increase (Decrease) in Stockholders' Equity
Balance	180,340
Net income	3,670
Preferred distributions	(3,670)
Balance	180,340
Series I Preferred Units
Increase (Decrease) in Stockholders' Equity
Balance	221,965
Net income	3,737
Preferred distributions	(3,737)
Preferred units issuance costs	(33)
Balance	$ 221,932