Derivatives and Hedging Activities (Schedule of Derivative Instruments in Statement of Financial Position, Fair Value) (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Derivatives, Fair Value [Line Items]
Derivative assets	$ 0	$ 1,892
Derivative liabilities	(8,194)	(6,922)
Interest Rate Swap [Member] | Not Designated as Hedging Instrument [Member] | Rent and Tenant Receivables and Other Assets, Net [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	0	98
Interest Rate Swap [Member] | Not Designated as Hedging Instrument [Member] | Deferred Rent, Derivative and Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	(723)	0
Cash Flow Hedging [Member] | Interest Rate Swap [Member] | Designated as Hedging Instrument [Member] | Rent and Tenant Receivables and Other Assets, Net [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	0	1,794
Cash Flow Hedging [Member] | Interest Rate Swap [Member] | Designated as Hedging Instrument [Member] | Deferred Rent, Derivative and Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liabilities	$ (7,471)	$ (6,922)