Investment in Real Estate Quantitative Information About Level 3 Fair Value Measurements (Details) $ in Thousands, ft² in Millions	Mar. 31, 2018 USD ($) ft² Property
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Number of industrial properties	485
Gross leasable area (GLA) of industrial properties | ft²	60.1
Unobservable Inputs (Level 3) | Contracted Price
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value of Industrial Property | $	$ 6,416
Number of industrial properties	1
Number of land parcels	1
Gross leasable area (GLA) of industrial properties | ft²	0.1