Redeemable Noncontrolling Interests (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended			9 Months Ended	12 Months Ended	0 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Sep. 30, 2013 Capital Unit, Class A [Member]	Dec. 31, 2012 Capital Unit, Class A [Member]	May 09, 2013 Series D15 Cumulative Redeemable Preferred Unit [Member]	Sep. 30, 2013 Cumulative Redeemable Preferred Unit [Member]	Dec. 31, 2012 Cumulative Redeemable Preferred Unit [Member]
Redeemable Noncontrolling Interests Rollforward [Abstract]
Reedemable Noncontrolling Interest, Beginning Balance	$ 944,152	$ 1,160,677
Net income	28,960	40,595
Other comprehensive loss	5,982	(15,717)
Distributions	(25,827)	(34,138)
Conversion Of Class A Redeemable Units At Redemption Value	(19,627)	(51,216)
Adjustment to carry redeemable Class A units at redemption value	43,709	63,657
Redemption of redeemable units	(36,900)	(168,300)		950,098	898,152
Other, net	10,649	(59)
Reedemable Noncontrolling Interest, Ending Balance	951,098	995,499
Redeemable Noncontrolling Interests Additional Disclosure [Abstract]
Redeemable Noncontrolling Interest, Equity, Common, Carrying Amount	950,098		898,152
Temporary Equity Dividend Rate Percentage						6.875%
Fair value of Series G convertible preferred units and Series D-13 cumulative redeemable preferred units							55,097	55,011
Aggregate face amount of Cumulative redeemable preferred units						45,000
Redemption of redeemable units	$ (36,900)	$ (168,300)		$ 950,098	$ 898,152