Investments in Real Estate (Purchase Price Allocation) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)
Business Acquisition [Line Items]
Land	$ 87,610
Buildings and Improvements	276,913
Tenant Improvements	1,582
Below-Market Leases	(1,495)
Acquisition Date Fair Value	415,764
Acquired above-market leases:
Business Acquisition [Line Items]
Intangibles	$ 21,043
Weighted average remaining intangible amortization life (in months)	65 months
Acquired in-place lease value
Business Acquisition [Line Items]
Intangibles	$ 30,111
Weighted average remaining intangible amortization life (in months)	81 months
Off-Market Favorable Lease
Business Acquisition [Line Items]
Weighted average remaining intangible amortization life (in months)	80 months
Land Parcels
Business Acquisition [Line Items]
Land	$ 55,229
Buildings and Improvements	0
Tenant Improvements	0
Below-Market Leases	0
Acquisition Date Fair Value	55,229
Land Parcels | Acquired above-market leases:
Business Acquisition [Line Items]
Intangibles	0
Land Parcels | Acquired in-place lease value
Business Acquisition [Line Items]
Intangibles	0
Data Centers
Business Acquisition [Line Items]
Land	20,431
Buildings and Improvements	275,374
Tenant Improvements	1,506
Below-Market Leases	(811)
Acquisition Date Fair Value	346,199
Data Centers | Acquired above-market leases:
Business Acquisition [Line Items]
Intangibles	21,043
Data Centers | Acquired in-place lease value
Business Acquisition [Line Items]
Intangibles	28,656
Technology Manufacturing
Business Acquisition [Line Items]
Land	11,950
Buildings and Improvements	1,539
Tenant Improvements	76
Below-Market Leases	(684)
Acquisition Date Fair Value	14,336
Technology Manufacturing | Acquired above-market leases:
Business Acquisition [Line Items]
Intangibles	0
Technology Manufacturing | Acquired in-place lease value
Business Acquisition [Line Items]
Intangibles	$ 1,455