Investment in Real Estate investment in Real Estate - Summary of Industrial Property Acquisiitions (Details) $ in Thousands, ft² in Millions		12 Months Ended
		Dec. 31, 2016 USD ($) ft² Property	Dec. 31, 2015 USD ($) ft² Property	Dec. 31, 2014 USD ($) ft² Property
Real Estate [Abstract]
Number of industrial properties acquired | Property		6	8	8
Gross leasable area (GLA) of industrial properties acquired | ft²		0.7	1.9	1.1
Purchase price of industrial properties acquired | $	[1]	$ 111,130	$ 169,218	$ 95,692

[1] (A) Purchase price includes the acquisition of several land parcels for the years ended 2016, 2015 and 2014 and excludes closing costs incurred with the acquisition of the industrial properties and land parcels.