Shareholders' Equity - Additional Information (Detail)		9 Months Ended
	Jan. 04, 2021	Sep. 30, 2022 USD ($) Property $ / shares shares	Sep. 30, 2021 USD ($) Property $ / shares shares	Aug. 11, 2022 USD ($)	Jun. 15, 2021 USD ($)	Dec. 29, 2020 USD ($)	Aug. 02, 2017 USD ($)
Stockholders Equity [Line Items]
Number of storage facilities acquired | Property		43	62
Buyback Program, authorized repurchase amount							$ 200,000,000
Stock repurchased during period, shares | shares		0	0
Shares issued under dividend reinvestment plan | shares		0	0
Description of stock split of common stock		three-for-two
Stock dividend payable percentage of common stock	50.00%
Description of additional share received		Shareholders of record at the close of business on January 15, 2021 received one additional share of Company stock for every two shares owned.
2020 Equity Program [Member]
Stockholders Equity [Line Items]
Common stock value authorized under equity offering program						$ 500,000,000
Common stock shares issued under equity offering program | shares			4,838,200
Weighted average issue price | $ / shares			$ 95.80
Proceeds from issuance of common stock			$ 458,200,000
Sales commissions paid			4,600,000
Other expenses			$ 700,000
2021 Equity Program [Member]
Stockholders Equity [Line Items]
Common stock value authorized under equity offering program					$ 500,000,000
Common stock shares issued under equity offering program | shares		1,352,833
Weighted average issue price | $ / shares		$ 135.22
Proceeds from issuance of common stock		$ 181,100,000
Sales commissions paid		$ 1,800,000
2022 Equity Program [Member]
Stockholders Equity [Line Items]
Common stock value authorized under equity offering program				$ 1,000,000,000