Stockholders' Equity (Detail)				7 Months Ended	9 Months Ended		12 Months Ended
	Jul. 20, 2023 USD ($) shares	Jan. 07, 2022 USD ($) store shares	Aug. 09, 2021 USD ($) sales_agent	Aug. 08, 2021 USD ($) shares	Sep. 30, 2023 USD ($) shares	Sep. 30, 2022 USD ($)	Dec. 31, 2022 USD ($) shares	Jul. 19, 2023 $ / shares	Oct. 15, 2020 USD ($)
Class of Stock [Line Items]
Issuance of common stock in conjunction with acquisitions (in shares) | shares	76,217,359	186,766
Issuance of common stock in conjunction with acquisitions	$ 11,353,338,000	$ 40,965,000				$ 40,963,000
Price per share (dollars per share) | $ / shares								$ 148.96
Number of stores acquired through issuance of common stock | store		2
Number of sales agents | sales_agent			10
Share repurchase program, authorized amount									$ 400,000,000
Repurchase of common stock, net of offering costs						$ 63,008,000	$ 63,008,000
Repurchase of common stock (in shares) | shares					0		381,786
Share repurchase program, remaining authorization					$ 336,992,000
Life Storage, Inc
Class of Stock [Line Items]
Equity interest issued conversion ratio | shares	0.895
At the Market Equity Distribution Agreement
Class of Stock [Line Items]
Aggregate offering price of common shares			$ 800,000,000
Shares issued (in shares) | shares				585,685
Net proceeds				$ 66,617,000