Acquired Intangible Assets, Net (Schedule of Acquired Intangible Assets, Net) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible asset, net of accumulated amortization	$ 174,190	$ 178,430
Acquired intangible asset, accumulated amortization	$ 57,612	$ 53,372
Acquired intangible asset, weighted average remaining life	13 years 3 months 18 days	13 years 6 months
In-place leases [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible asset, net of accumulated amortization	$ 168,644	$ 172,791
Acquired intangible asset, accumulated amortization	$ 55,984	$ 51,837
Acquired intangible asset, weighted average remaining life	12 years 8 months 12 days	12 years 10 months 24 days
Above-market leases [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible asset, net of accumulated amortization	$ 2,977	$ 3,057
Acquired intangible asset, accumulated amortization	$ 1,383	$ 1,303
Acquired intangible asset, weighted average remaining life	10 years	10 years 3 months 18 days
Ground lease interest [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible asset, net of accumulated amortization	$ 2,569	$ 2,582
Acquired intangible asset, accumulated amortization	$ 245	$ 232
Acquired intangible asset, weighted average remaining life	59 years 3 months 18 days	59 years 6 months