Investment in Real Estate Investment in Real Estate - Quantitative Information About Level 3 Fair Value Measurements (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014 sqft Property	Jun. 30, 2013 Unobservable Inputs (Level 3) Contracted Price [Member] sqft Property
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair value of industrial properties		$ 6,993	[1]
Number of industrial properties	653	4
Gross leasable area (GLA) of industrial properties	64,300,000	300,000

[1] The fair value for the properties was based upon the value of a third party purchase contract or letter of intent, which was subject to our corroboration for reasonableness.