XML 77 R46.htm IDEA: XBRL DOCUMENT v2.3.0.15
Properties, net (Details 6)
9 Months Ended12 Months Ended
Sep. 30, 2011
sqfeet
property
Dec. 31, 2010
sqfeet
Fully operational office properties
  
2011 Construction and Redevelopment Activities  
Number of real estate properties2 
Square footage of real estate properties (in square feet)228,000 
Square feet placed in service on properties as of prior year end (in square feet) 79,000
Fully operational office properties | Baltimore/Washington Corridor
  
2011 Construction and Redevelopment Activities  
Number of real estate properties1 
Fully operational office properties | Greater Baltimore
  
2011 Construction and Redevelopment Activities  
Number of real estate properties1 
Properties under construction
  
2011 Construction and Redevelopment Activities  
Number of real estate properties10 
Square footage of real estate properties (in square feet)1,200,000 
Properties under construction | Baltimore/Washington Corridor
  
2011 Construction and Redevelopment Activities  
Number of real estate properties4 
Properties under construction | Greater Baltimore
  
2011 Construction and Redevelopment Activities  
Number of real estate properties2 
Properties under construction | San Antonio
  
2011 Construction and Redevelopment Activities  
Number of real estate properties1 
Properties under construction | Northern Virginia
  
2011 Construction and Redevelopment Activities  
Number of real estate properties1 
Properties under construction | Huntsville
  
2011 Construction and Redevelopment Activities  
Number of real estate properties1 
Properties under construction | St. Mary's County
  
2011 Construction and Redevelopment Activities  
Number of real estate properties1 
Properties under redevelopment
  
2011 Construction and Redevelopment Activities  
Number of real estate properties2 
Square footage of real estate properties (in square feet)297,000 
Properties under redevelopment | Northern Virginia
  
2011 Construction and Redevelopment Activities  
Number of real estate properties1 
Properties under redevelopment | Greater Philadelphia
  
2011 Construction and Redevelopment Activities  
Number of real estate properties1 
Partially operational office properties | Baltimore/Washington Corridor
  
2011 Construction and Redevelopment Activities  
Number of real estate properties1 
Square feet placed in service on properties during the period (in square feet)61,000