Real Estate - Summary of Acquisition (Detail) ft² in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019 USD ($) ft² a Property	Sep. 30, 2018 USD ($) ft² a Property	Sep. 30, 2019 USD ($) ft² a Property	Sep. 30, 2018 USD ($) ft² a Property
Business Acquisition [Line Items]
Number of operating properties | Property	2	5	15	8
Square feet of operating properties | ft²	80	523	1,083	1,406
Acquisition cost of net investments in real estate properties | $	$ 184,077	$ 183,484	$ 701,264	$ 497,783
Acquisitions of Properties from Third Parties [Member] | Land [Member]
Business Acquisition [Line Items]
Acres of land | a	186	166	651	974