Organization and Basis of Presentation (Details)	Jun. 30, 2018 property subsidiary
Real Estate Properties [Line Items]
Number of wholly-owned subsidiaries jointly elected to be treated as a TRS | subsidiary	1
Wholly-owned
Real Estate Properties [Line Items]
Number of real estate properties owned	107
Wholly-owned | Retail | Operating properties
Real Estate Properties [Line Items]
Number of real estate properties owned	105
Reisterstown Road Plaza | Wholly-owned | Redevelopment properties
Real Estate Properties [Line Items]
Number of real estate properties owned	1
Redevelopment portion of Circle East, formerly known as Towson Circle | Wholly-owned | Redevelopment properties
Real Estate Properties [Line Items]
Number of real estate properties owned	0
Carillon, formerly known as Boulevard at the Capital Centre | Wholly-owned | Future redevelopment property
Real Estate Properties [Line Items]
Number of real estate properties owned	1