Real Estate Activities Real Estate Activities - Impairment of Assets (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Mar. 31, 2015	Jun. 30, 2015	Jun. 30, 2014
Impairment of assets and expensed project costs			$ 35,145	$ 17,659
Uniontown Mall [Member]
Impairment Of Assets	$ 1,300	$ 6,200
Gadsden Mall [Member]
Impairment Of Assets	$ 27,300