Developments of Consolidated Outlet Centers (Narrative) (Details) $ in Millions	1 Months Ended
	Sep. 30, 2016 USD ($) ft²	Nov. 30, 2015 USD ($)	Jul. 31, 2016 ft²	May 31, 2016 ft²	Dec. 31, 2015 ft²	[1]
Savannah [Member]
Square Feet				419,000	377,000
Daytona Beach [Member]
Payments to acquire land | $		$ 9.9
Square Feet	352,000
Fort Worth [Member]
Payments to acquire land | $	$ 11.2
Square Feet	352,000
Lancaster [Member]
Square Feet	123,000		123,000

[1] Based on capital contribution and distribution provisions in the joint venture agreement, our economic interest in the venture's cash flow was greater than indicated in the Ownership column, which states our legal interest in this venture. As of December 31, 2015, based upon the liquidation proceeds we would receive from a hypothetical liquidation of our investment based on depreciated book value, our estimated economic interest in the venture was approximately 98%. Our economic interest may fluctuate based on a number of factors, including mortgage financing, partnership capital contributions and distributions, and proceeds from gains or losses of asset sales.