Real Estate - Summary of Acquisition (Detail) ft² in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019 USD ($) ft² a Property	Jun. 30, 2018 USD ($) ft² a Property	Jun. 30, 2019 USD ($) ft² a Property	Jun. 30, 2018 USD ($) ft² a Property
Business Acquisition [Line Items]
Number of operating properties | Property	1	3	13	3
Square feet of operating properties | ft²	36	883	1,003	883
Acquisition cost of net investments in real estate properties | $	$ 204,935	$ 179,358	$ 517,187	$ 314,299
Acquisitions of Properties from Third Parties [Member] | Land [Member]
Business Acquisition [Line Items]
Acres of land | a	277	429	465	808