Investments in Unconsolidated Companies (Narrative) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) entities	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Schedule of Equity Method Investments [Line Items]
Number of unconsolidated joint ventures in which equity interests held | entities	16
Impairment Charges	$ 22,932	$ 49,106	$ 3,777
Fair Value Inputs, Discount Rate	7.07%
Fair Value Inputs, Cap Rate	5.57%
Equity Method Investments [Member]
Schedule of Equity Method Investments [Line Items]
Impairment Charges	$ 30,000
Number of Impaired Joint Ventures [Member]
Schedule of Equity Method Investments [Line Items]
Number of unconsolidated joint ventures in which equity interests held | entities	3
buildings [Member]
Schedule of Equity Method Investments [Line Items]
Impairment Charges	$ 3,406	$ 15,406	0
Fair Value Inputs, Cap Rate		8.50%
Land [Member]
Schedule of Equity Method Investments [Line Items]
Impairment Charges	19,526	$ 33,700	$ 3,777
Minimum [Member]
Schedule of Equity Method Investments [Line Items]
Fair Value Inputs, Discount Rate		7.38%
Fair Value Inputs, Cap Rate		5.98%
Maximum [Member]
Schedule of Equity Method Investments [Line Items]
Fair Value Inputs, Discount Rate		9.96%
Fair Value Inputs, Cap Rate		8.36%
Linden, New Jersey [Member] | Land [Member] | Equity Method Investments [Member]
Schedule of Equity Method Investments [Line Items]
Impairment Charges	$ 19,500