Redeemable Noncontrolling Interests (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Redeemable Noncontrolling Interests Rollforward [Abstract]
Reedemable Noncontrolling Interest, Beginning Balance	$ 1,003,620	$ 944,152
Net Income	16,552	28,960
Other comprehensive income	(109)	5,982
Distributions	(25,166)	(25,827)
Redemption of Class A units for common shares, at redemption value	(22,668)	(19,627)
Adjustments to carry redeemable Class A units at redemption value	144,231	43,709
Redemption of Series D-15 redeemable units		(36,900)
Other, net	23,592	10,649
Reedemable Noncontrolling Interest, Ending Balance	1,140,052	951,098
Redeemable Noncontrolling Interests Additional Disclosure [Abstract]
Redeemable Noncontrolling Interest, Equity, Common, Carrying Amount	1,139,052		1,002,620
Common Class A [Member]
Redeemable Noncontrolling Interests Additional Disclosure [Abstract]
Redeemable Noncontrolling Interest, Equity, Common, Carrying Amount	1,139,052		1,002,620
Cumulative Redeemable Preferred Unit [Member]
Redeemable Noncontrolling Interests Additional Disclosure [Abstract]
Fair value of Series G convertible preferred units and Series D-13 cumulative redeemable preferred units	$ 55,097		$ 55,097