Commitments and Contingencies - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013 sqft building
Commitments and Contingencies Disclosure [Abstract]
Number of industrial properties committed to development	4
Gross leasable area (GLA) of industrial properties committed to development	1,800,000
Estimated total construction costs	$ 128,600
Estimated total construction costs remaining to be funded	$ 34,200