Basis of Presentation (Details) - property	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
Real Estate Properties
Total number of joint venture properties	82
Number of joint venture properties managed by the entity	58
Number of International joint venture properties	19
Number of joint venture properties managed by others	24
Ownership interest:
Ownership percentage in the Operating Partnership	85.50%	85.50%
McArthurGlen Group
Real Estate Properties
Number of properties	5
Weighted average
Ownership interest:
Ownership percentage in the Operating Partnership	85.50%		85.60%
Wholly owned properties
Real Estate Properties
Number of properties	135
Partially owned properties
Real Estate Properties
Number of properties	13