Real Estate Properties Acquired ,Developed and/or Disposed (Detail)	18 Months Ended
	Jun. 30, 2013
Business Acquisition One
Real Estate Properties [Line Items]
Name of Property	1500 Rockville Pike
Location	Rockville, MD
Type	Shopping Center
Year of Acquisition	2012
Business Acquisition Two
Real Estate Properties [Line Items]
Name of Property	5541 Nicholson Lane
Location	Rockville, MD
Type	Shopping Center
Year of Acquisition	2012
Business Disposition One
Real Estate Properties [Line Items]
Name of Property	West Park
Location	Oklahoma City, OK
Type	Shopping Center
Year of Disposition	2012
Business Disposition Two
Real Estate Properties [Line Items]
Name of Property	Belvedere
Location	Baltimore, MD
Type	Shopping Center
Year of Disposition	2012