Business Combinations (Transactions Related to Acquisitions) (Details) (USD $)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Business Acquisition [Line Items]
Fair value of our equity interest before acquisition					$ 3,825,000
Fair value of consideration transferred					218,481,000	[1]
Assets:
Property					195,377,000
Unamortized debt and lease costs					36,787,000
Restricted deposits and mortgage escrows					395,000
Other, net					3,742,000
Liabilities:
Debt, net					(46,923,000)	[2]
Accounts payable and accrued expenses					(2,250,000)
Other, net					(5,899,000)
Total net assets					181,229,000
Acquisition costs (included in operating expenses)					1,391,000
Gain on acquisition	0	1,869,000	0	1,869,000	1,869,000
Debt assumption					37,800,000
Debt previously recorded					$ 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.