Organization (Details)	Mar. 31, 2018 state country property
U.S. and Puerto Rico
Real Estate Properties
Number of properties	206
Number of U.S. states containing property locations | state	37
U.S. and Puerto Rico | Malls
Real Estate Properties
Number of properties	107
U.S. and Puerto Rico | Premium Outlets
Real Estate Properties
Number of properties	68
U.S. and Puerto Rico | The Mills
Real Estate Properties
Number of properties	14
U.S. and Puerto Rico | Community/Lifestyle Centers
Real Estate Properties
Number of properties	4
U.S. and Puerto Rico | Other shopping centers or outlet centers
Real Estate Properties
Number of properties	13
Japan | Premium Outlets
Real Estate Properties
Number of properties	9
South Korea | Premium Outlets
Real Estate Properties
Number of properties	4
Canada | Premium Outlets
Real Estate Properties
Number of properties	2
Canada | Designer Outlets
Real Estate Properties
Number of properties	1
Malaysia | Premium Outlets
Real Estate Properties
Number of properties	2
Mexico | Premium Outlets
Real Estate Properties
Number of properties	1
Europe | Klepierre
Real Estate Properties
Ownership percentage	21.10%
Number of countries | country	16
Europe | Designer Outlets
Real Estate Properties
Number of properties	8
Europe | Designer Outlets | Consolidated properties
Real Estate Properties
Number of properties	6
Italy | Designer Outlets
Real Estate Properties
Number of properties	2
Netherlands | Designer Outlets
Real Estate Properties
Number of properties	2
Austria | Designer Outlets
Real Estate Properties
Number of properties	1
France | Designer Outlets
Real Estate Properties
Number of properties	1
Germany | Designer Outlets
Real Estate Properties
Number of properties	1
United Kingdom | Designer Outlets
Real Estate Properties
Number of properties	1