Real Estate - Summary of Acquisition (Detail) ft² in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) ft² a Property	Dec. 31, 2018 USD ($) ft² a Property	Dec. 31, 2017 USD ($) ft² a Property
Business Acquisition [Line Items]
Number of operating properties | Property	22	20	16
Square feet | ft²	1,405	4,757	6,859
Acquisition cost of net investments in real estate properties | $	$ 1,074,815	$ 1,008,718	$ 1,139,410
Acquisitions of Properties from Third Parties [Member] | Land [Member]
Business Acquisition [Line Items]
Acres of land | a	1,269	1,210	1,392