Debt (Mortgage Notes Payable) (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Loss on derivative instruments, net	$ (1,460)	$ (10,570)	$ (67,946)
Extinguishment and forgiveness of debt, net	$ (4,812)	21,869	$ 0
Weighted-Average Interest Rate	3.75%
Weighted-average years to maturity	3 years 9 months 18 days
Mortgage Notes Payable [Member]
Debt Instrument [Line Items]
Weighted-Average Interest Rate	4.39%
Mortgage Notes Payable [Member]
Debt Instrument [Line Items]
Repayments and extinguishment	$ 548,900	1,600,000
Payments for prepayments fees	102	35,900
Extinguishment and forgiveness of debt, net	$ (41)	(18,300)
Weighted-Average Interest Rate	5.08%
Principal balance	$ 38,100	53,800
Gain on forgiveness of debt	$ 4,900
Default rate of interest, per annum	10.68%
Mortgage Notes Payable [Member] | Weighted-Average [Member]
Debt Instrument [Line Items]
Weighted-average years to maturity	5 years 1 month 2 days
Mortgage Notes Payable [Member] | Interest Rate Swap [Member]
Debt Instrument [Line Items]
Loss on derivative instruments, net		11,400
Mortgage Notes Payable [Member] | Mortgage Notes Payable [Member] | Weighted-Average [Member]
Debt Instrument [Line Items]
Weighted-average years to maturity	13 years 4 months 2 days
Other Debt [Member]
Debt Instrument [Line Items]
Repayments and extinguishment		100,000
Extinguishment and forgiveness of debt, net		$ 4,300