Investments in real estate, net Land undergoing predevelopment and future development (Details)	Jun. 30, 2014 sqft
Real Estate Properties [Line Items]
Area of Real Estate Property	17,881,108
Land undergoing predevelopment activities (CIP) in North America (2) | North America [Member]
Real Estate Properties [Line Items]
Area of Real Estate Property	2,474,163
Land undergoing predevelopment activities (CIP) in North America (2) | Alexandria Center™ at Kendall Square
Real Estate Properties [Line Items]
Area of Real Estate Property	1,100,000
Land held for future development in North America
Real Estate Properties [Line Items]
Number of construction or preconstruction activities	0
Land held for future development in North America | North America [Member]
Real Estate Properties [Line Items]
Area of Real Estate Property	3,155,401