Related Parties (Narrative) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) property	Dec. 31, 2014 USD ($) property	Dec. 31, 2013 USD ($) property
Related Party Transaction [Line Items]
Net accounts receivable, related parties	$ 1,200	$ 1,500
Accounts payable and accrued expenses, related parties	5,200	6,000
Management fees revenues, related parties	$ 4,500	$ 4,600	$ 5,000
Number of real estate properties | property	2	2
Total assets	$ 3,901,945	$ 3,805,915
Debt, net	$ 1,879,841
Number of centers sold | property	11
Increase in equity	$ 0	11,015	(16,177)
Gain on sale of property	$ 59,621	190,872	119,965
Disposition of noncontrolling interests		(144,263)
Decrease in noncontrolling interests		$ 0	$ 0
Hines [Member]
Related Party Transaction [Line Items]
Ownership percentage in joint ventures		30.00%
Number of real estate properties | property		5	13
Total assets			$ 172,900
Debt, net			$ 11,100
Number of centers sold | property		8
Increase in equity		$ 11,000
Gain on sale of property		23,300
Disposition of noncontrolling interests		144,300
Decrease in noncontrolling interests		$ (11,000)