Commitments and Contingencies - Additional Information (Detail) $ in Thousands, ft² in Millions	Sep. 30, 2015 USD ($) ft² Property
Commitments and Contingencies Disclosure [Abstract]
Number of industrial properties under construction | Property	9
Gross leasable area (GLA) of industrial properties under construction | ft²	2.2
Estimated total investment	$ 148,200
Estimated total investment remaining to be funded	$ 73,100