Acquired Intangible Assets, Net (Schedule of Acquired Intangible Assets, Net) (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible asset, net of accumulated amortization	$ 201,710	$ 197,530
Acquired intangible asset, accumulated amortization	$ 46,129	$ 37,374
Acquired intangible asset, weighted average remaining life	14 years 10 months 24 days	14 years 10 months 24 days
In-place leases [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible asset, net of accumulated amortization	$ 195,882	$ 191,470
Acquired intangible asset, accumulated amortization	$ 44,783	$ 36,260
Acquired intangible asset, weighted average remaining life	14 years 4 months 24 days	14 years 3 months 18 days
Above-market leases [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible asset, net of accumulated amortization	$ 3,221	$ 3,428
Acquired intangible asset, accumulated amortization	$ 1,139	$ 932
Acquired intangible asset, weighted average remaining life	10 years 8 months 12 days	11 years 1 month 6 days
Ground lease interest [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible asset, net of accumulated amortization	$ 2,607	$ 2,632
Acquired intangible asset, accumulated amortization	$ 207	$ 182
Acquired intangible asset, weighted average remaining life	60 years	60 years 4 months 24 days