Summary Of Significant Accounting Policies (Recently Adopted Accounting Pronouncements) (Details) $ in Thousands	Dec. 31, 2016 USD ($)	Jan. 01, 2016 USD ($)	Dec. 31, 2015 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net real estate assets of VIEs previously consolidated as voting interest entities	$ 1,017,700
Mortgage Payable From Consolidated Variable Interest Entities	439,120		$ 448,315
Maximum exposure to loss in variable interest entity	439,100
Pike and Rose Hotel JV
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Investment in variable interest entity		$ 6,600
Maximum exposure to loss in variable interest entity	$ 13,500	$ 13,500
Adjustments for New Accounting Pronouncement
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Unamortized debt issuance costs			$ 15,200
Adjustments for New Accounting Pronouncement | Previous voting interest entity
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of variable interest entities previously consolidated as voting interest entities		10
Net real estate assets of VIEs previously consolidated as voting interest entities		$ 566,100
Mortgage Payable From Consolidated Variable Interest Entities		$ 194,900