Significant Accounting Policies (Details 3) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Noncontrolling Interests:
Balance			$ 6,822,632,000
Purchase and disposition of noncontrolling interests, net, and other			47,409,000
Balance	6,115,608,000		6,115,608,000
Temporary Equity
Contribution to Noncontrolling Interest Partnership	83,000,000
Noncontrolling Interest Preferred Return Percentage	2.50%
Noncontrolling Interests
Noncontrolling Interests:
Balance	(1,306,000)	(931,000)	4,264,000	(877,000)
Net Income attributable to noncontrolling nonredeemable interests	939,000	23,000	970,000	26,000
Distributions to noncontrolling nonredeemable interestholders	(5,876,000)	(119,000)	(17,607,000)	(178,000)
Purchase and disposition of noncontrolling interests, net, and other	4,600,000	(2,000)	10,730,000
Balance	(1,643,000)	(1,029,000)	(1,643,000)	(1,029,000)
Temporary Equity
Noncontrolling Interests Redeemable at Amount in Excess of Fair Value	$ 0		$ 0
7.5% Cumulative Redeemable Preferred Units | Noncontrolling Interests
Temporary Equity
Dividend rate on cumulative redeemable preferred units (as a percent)			7.50%