Derivative Instruments and Hedging Activities Derivative Instrument and Hedging Activities Notional Table (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Derivative [Line Items]
Fair Value	$ 15,639	$ 0	$ 12,106	$ 0
Interest Rate Swap [Member]
Derivative [Line Items]
Notional Amount	475,000		475,000
Fair Value			12,106
Operating Partnership [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Notional Amount	$ 325,000		$ 325,000
Strike Price	2.458%		2.458%
Fair Value			$ 9,817
Operating Partnership [Member] | Interest Rate Swap [Member] | Interest Rate Swap 2.571% [Member]
Derivative [Line Items]
Notional Amount	$ 50,000		$ 50,000
Strike Price	2.571%		2.571%
Fair Value			$ 1,003
Operating Partnership [Member] | Interest Rate Swap [Member] | Interest Rate Swap 2.476% [Member]
Derivative [Line Items]
Notional Amount	$ 75,000		$ 75,000
Strike Price	2.476%		2.476%
Fair Value			$ 2,172
Operating Partnership [Member] | Interest Rate Swap [Member] | Interest Rate Swap 2.523% [Member]
Derivative [Line Items]
Notional Amount	$ 50,000		$ 50,000
Strike Price	2.523%		2.523%
Fair Value			$ 1,215
Operating Partnership [Member] | Interest Rate Swap [Member] | Interest Rate Swap 2.480% [Member]
Derivative [Line Items]
Notional Amount	$ 50,000		$ 50,000
Strike Price	2.48%		2.48%
Fair Value			$ 1,402
Operating Partnership [Member] | Interest Rate Swap [Member] | Interest Rate Swap 2.348%Member]
Derivative [Line Items]
Notional Amount	$ 25,000		$ 25,000
Strike Price	2.348%		2.348%
Fair Value			$ 1,008
Operating Partnership [Member] | Interest Rate Swap [Member] | Interest Rate Swap 2.249% [Member]
Derivative [Line Items]
Notional Amount	$ 25,000		$ 25,000
Strike Price	2.249%		2.249%
Fair Value			$ 1,208
Operating Partnership [Member] | Interest Rate Swap [Member] | Interest Rate Swap 2.242% [Member]
Derivative [Line Items]
Notional Amount	$ 25,000		$ 25,000
Strike Price	2.242%		2.242%
Fair Value			$ 1,242
Operating Partnership [Member] | Interest Rate Swap [Member] | Interest Rate Swap 2.541% [Member]
Derivative [Line Items]
Notional Amount	$ 25,000		$ 25,000
Strike Price	2.541%		2.541%
Fair Value			$ 567
767 Fifth Partners LLC [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Notional Amount	$ 150,000		$ 150,000
Strike Price	2.793%		2.793%
Fair Value			$ 2,289
767 Fifth Partners LLC [Member] | Interest Rate Swap [Member] | Interest Rate Swap 2.683% [Member]
Derivative [Line Items]
Notional Amount	$ 25,000		$ 25,000
Strike Price	2.683%		2.683%
Fair Value			$ 618
767 Fifth Partners LLC [Member] | Interest Rate Swap [Member] | Interest Rate Swap 2.677% [Member]
Derivative [Line Items]
Notional Amount	$ 50,000		$ 50,000
Strike Price	2.677%		2.677%
Fair Value			$ 1,261
767 Fifth Partners LLC [Member] | Interest Rate Swap [Member] | Interest Rate Swap 2.913% [Member]
Derivative [Line Items]
Notional Amount	$ 25,000		$ 25,000
Strike Price	2.913%		2.913%
Fair Value			$ 123
767 Fifth Partners LLC [Member] | Interest Rate Swap [Member] | Interest Rate Swap 2.857% [Member]
Derivative [Line Items]
Notional Amount	$ 25,000		$ 25,000
Strike Price	2.857%		2.857%
Fair Value			$ 244
767 Fifth Partners LLC [Member] | Interest Rate Swap [Member] | Interest Rate Swap 2.950% [Member]
Derivative [Line Items]
Notional Amount	$ 25,000		$ 25,000
Strike Price	2.95%		2.95%
Fair Value			$ 43