Redeemable Noncontrolling Interests (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Redeemable Noncontrolling Interest Units Table [Abstract]
Redeemable Noncontrolling Interest, Equity, Common, Carrying Amount	$ 1,223,793	$ 1,336,780
Redeemable Noncontrolling Interest, Equity, Preferred, Carrying Amount	5,428	1,000
Redeemable Noncontrolling Interests Rollforward [Abstract]
Reedemable Noncontrolling Interest, Beginning Balance	1,337,780	1,003,620
Net income	43,231	47,613	$ 24,817
Other comprehensive income	(2,866)	1,323	5,296
Distributions	(30,263)	(33,469)
Other, net	37,605	30,690
Reedemable Noncontrolling Interest, Ending Balance	1,229,221	1,337,780	$ 1,003,620
Common Class A [Member]
Redeemable Noncontrolling Interest Units Table [Abstract]
Redeemable Noncontrolling Interest, Equity, Common, Carrying Amount	$ 1,223,793	$ 1,336,780
Outstanding Partnership Units held by Third Parties	12,242,820	11,356,550
Preferred Or Annual Distribution Rate (in dollars per share)	$ 2.52
Redeemable Noncontrolling Interests Rollforward [Abstract]
Redemption of Class A units for common shares, at redemption value	$ (48,230)	$ (27,273)
Adjustments to carry redeemable Class A units at redemption value	(192,464)	315,276
Issuance of Units	80,000
Series D16 Cumulative Redeemable Preferred Unit [Member]
Redeemable Noncontrolling Interest Units Table [Abstract]
Redeemable Noncontrolling Interest, Equity, Preferred, Carrying Amount	$ 1,000	$ 1,000
Outstanding Partnership Units held by Third Parties	1	1
Par or Stated Value Per Share	$ 1,000,000.00
Preferred Or Annual Distribution Rate (in dollars per share)	$ 50,000.00
Dividend Percentage	5.00%
Series D17 Cumulative Redeemable Preferred Unit [Member]
Redeemable Noncontrolling Interest Units Table [Abstract]
Redeemable Noncontrolling Interest, Equity, Preferred, Carrying Amount	$ 4,428	$ 0
Outstanding Partnership Units held by Third Parties	177,100	0
Par or Stated Value Per Share	$ 25.00
Preferred Or Annual Distribution Rate (in dollars per share)	$ 0.8125
Dividend Percentage	3.25%
Redeemable Noncontrolling Interests Rollforward [Abstract]
Issuance of Units	$ 4,428
Cumulative Redeemable Preferred Unit [Member]
Redeemable Noncontrolling Interest Units Table [Abstract]
Outstanding Partnership Units held by Third Parties	177,101	1
Redeemable Noncontrolling Interests Additional Disclosure [Abstract]
Fair value of Series G convertible preferred units and Series D-13 cumulative redeemable preferred units	$ 50,561	$ 55,097