Summary Of Significant Accounting Policies Recently Adopted Accounting Pronouncements (Details) - USD ($)	Mar. 31, 2016	Dec. 31, 2015
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Mortgages payable of VIEs previously consolidated as voting interest entities	$ 446,046,000	$ 448,315,000
Pike and Rose Hotel JV
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Investment in variable interest entity	7,200,000
Maximum exposure to loss in variable interest entity	$ 13,500,000
Adjustments for New Accounting Pronouncement
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of variable interest entities previously consolidated as voting interest entities	10
Unamortized Debt Issuance Costs		$ 15,200,000
Adjustments for New Accounting Pronouncement | Previous voting interest entity
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net real estate assets of VIEs previously consolidated as voting interest entities	$ 565,700,000
Mortgages payable of VIEs previously consolidated as voting interest entities	$ 193,900,000