Real Estate Investments (Summary of Amortization Expense and Adjustments) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Finite-Lived Intangible Assets [Line Items]
Amortization of lease assets			$ 18,633	$ 12,114
Depreciation and Amortization [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization of lease assets	$ 9,269	$ 6,344	18,633	12,114
Depreciation and Amortization [Member] | In-place leases [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization of lease assets	9,269	6,344	18,633	12,114
Rental Income [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization expense (accretion income) of intangibles	755	633	1,541	1,200
Rental Income [Member] | Above-market lease assets [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization of lease assets	1,113	615	2,130	1,198
Rental Income [Member] | Below-market lease liabilities [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization of below market leases	1,868	1,248	3,671	2,398
Property Operating Expense [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization of lease assets	9	9	19	19
Property Operating Expense [Member] | Below Market Ground Lease [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization of lease assets	$ 9	$ 9	$ 19	$ 19