Business Combinations Business Combinations (Transactions Related to Acquisitions) (Details) (USD $)	3 Months Ended			9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011	Sep. 30, 2012		Sep. 30, 2011
Business Acquisition [Line Items]
Fair value of our equity interest before acquisition	$ 3,825,000			$ 3,825,000
Fair value of consideration transferred	218,481,000	[1]		218,481,000	[1]
Property	195,377,000			195,377,000
Unamortized debt and lease costs	36,787,000			36,787,000
Restricted deposits and mortgage escrows	395,000			395,000
Other, net	3,742,000			3,742,000
Debt, net	(46,923,000)	[2]		(46,923,000)	[2]
Accounts payable and accrued expenses	(2,250,000)			(2,250,000)
Other, net	(5,899,000)			(5,899,000)
Total net assets	181,229,000			181,229,000
Acquisition costs (included in operating expenses)	1,369,000			1,369,000
Gain on acquisition	1,869,000		0	1,869,000		0
Debt assumption	37,800,000			37,800,000
Debt previously recorded	$ 6,300,000			$ 6,300,000

[1] Includes assumption of debt totaling $37.8 million.

[2] Represents the fair value of debt, which includes $6.3 million that was previously recorded.