Investment in Storage Facilities and Intangible Assets - Additional Information (Detail) $ / shares in Units, $ in Thousands	3 Months Ended
Mar. 31, 2021 USD ($) Property $ / shares	Mar. 31, 2020 USD ($) Property
Investment Holdings [Line Items]
Number of storage facilities acquired \| Property	16	6
Cash payment for property acquisition	$ 265,197
Received return on investment	2,547	$ 3,611
Net other liabilities assumed	$ 1,000
Amortization period for in-place customer leases on a straight-line basis	12 months
Increase in depreciation expense due to facility replacement	$ 1,400
Estimate increase in depreciation expense due to facility replacement during remainder of 2021	$ 400
Accelerated depreciation reduced basic and diluted earnings per share \| $ / shares	$ 0.02
Depreciation and Amortization Expense [Member]
Investment Holdings [Line Items]
Amortization expense related to in-place customer leases	$ 2,100	$ 1,300
SNL Orix Merrick [Member]
Investment Holdings [Line Items]
Company common ownership interest	5.00%
Cash payment for property acquisition	$ 47,900
Received return on investment	$ 800

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Cash payments to acquire real estate.

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