Organization and Description of Business (Narrative) (Details)	Dec. 31, 2016 property
Organization and Description of Business [Line Items]
Number of real estate properties	145
Common Interest
Organization and Description of Business [Line Items]
Ownership percentage in the Operating Partnership	98.50%
Preferred Interest
Organization and Description of Business [Line Items]
Ownership percentage in the Operating Partnership	100.00%
North America
Organization and Description of Business [Line Items]
Number of real estate properties	104
Europe
Organization and Description of Business [Line Items]
Number of real estate properties	32
Asia
Organization and Description of Business [Line Items]
Number of real estate properties	4
Australia
Organization and Description of Business [Line Items]
Number of real estate properties	3
Canada
Organization and Description of Business [Line Items]
Number of real estate properties	2
Unconsolidated Properties
Organization and Description of Business [Line Items]
Number of real estate properties	14