Commitments and Contingencies - Additional Information (Details) $ in Thousands, ft² in Millions	Sep. 30, 2019 USD ($) ft² Property
Other Commitments [Line Items]
Number of industrial properties | Property	459
Gross leasable area (GLA) of industrial properties | ft²	62.7
Development Activity
Other Commitments [Line Items]
Number of industrial properties | Property	13
Gross leasable area (GLA) of industrial properties | ft²	3.3
Estimated total investment | $	$ 270,100
Estimated total investment remaining to be funded | $	$ 110,100