Redeemable Noncontrolling Interests (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Redeemable Noncontrolling Interest Units Table [Abstract]
Redeemable Noncontrolling Interest, Equity, Common, Carrying Amount	$ 1,087,466		$ 1,087,466		$ 1,336,780
Redeemable Noncontrolling Interests Rollforward [Abstract]
Reedemable Noncontrolling Interest, Beginning Balance			1,337,780	$ 1,003,620
Net income	10,198	$ 4,704	15,485	8,564
Other comprehensive income (loss)			(2,635)	1,260
Distributions			(14,734)	(16,824)
Other, net			25,370	16,771
Reedemable Noncontrolling Interest, Ending Balance	1,092,894	$ 1,220,958	1,092,894	1,220,958
Common Class A [Member]
Redeemable Noncontrolling Interest Units Table [Abstract]
Redeemable Noncontrolling Interest, Equity, Common, Carrying Amount	1,087,466		1,087,466		1,336,780
Redeemable Noncontrolling Interests Rollforward [Abstract]
Redemption of Class A units for common shares, at redemption value			(43,278)	(19,771)
Adjustment to carry Class A redeemable units at redemption value			(229,521)	$ 227,338
Series D17 Cumulative Redeemable Preferred Unit [Member]
Redeemable Noncontrolling Interests Rollforward [Abstract]
Issuance of Series D-17 Preferred Units			4,427
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		$ 55,097