Basis of Presentation (Details) - property	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Real Estate Properties
Total number of joint venture properties	78	81
Number of joint venture properties managed by the entity	57
Number of International joint venture properties	17
Number of joint venture properties managed by others	21
Ownership interest:
Weighted average ownership in the Operating Partnership (as a percent)	86.50%	85.60%	85.50%
Ownership interest in the Operating Partnership (as a percent)	86.90%	85.70%
Wholly owned properties
Real Estate Properties
Number of properties	134
Partially owned properties
Real Estate Properties
Number of properties	17