Segment Information - Schedule of Financial Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Segment Reporting Information [Line Items]
Revenues:	$ 748,034	$ 498,902	$ 1,762,470	$ 1,417,452
Operating expenses:	448,242	229,045	925,797	650,869
Net operating income:	299,792	269,857	836,673	780,832
Management fees and other income	28,019	22,246	71,609	62,720
Transaction costs	0	0	0	(1,465)
Life Storage Merger transition costs	(54,174)	0	(54,174)	0
General and administrative expense	(37,406)	(32,275)	(107,011)	(93,288)
Depreciation and amortization expense	(152,338)	(71,423)	(309,914)	(208,396)
Gain on real estate transactions	0	0	0	14,249
Interest expense	(122,899)	(56,245)	(289,370)	(146,249)
Interest income	22,092	18,125	62,607	52,174
Equity in earnings and dividend income from unconsolidated real estate entities	15,043	11,149	38,602	30,436
Income tax expense	(6,944)	(6,760)	(17,238)	(15,516)
Net income	198,856	236,126	623,046	701,677
Operating Segments
Segment Reporting Information [Line Items]
Revenues:	720,015	476,656	1,690,861	1,354,732
Operating expenses:	204,324	125,347	454,698	347,720
Net operating income:	515,691	351,309	1,236,163	1,007,012
Self-Storage Operations | Operating Segments
Segment Reporting Information [Line Items]
Revenues:	650,887	428,787	1,525,596	1,216,639
Operating expenses:	185,194	114,577	416,997	322,371
Net operating income:	465,693	314,210	1,108,599	894,268
Tenant Reinsurance | Operating Segments
Segment Reporting Information [Line Items]
Revenues:	69,128	47,869	165,265	138,093
Operating expenses:	19,130	10,770	37,701	25,349
Net operating income:	$ 49,998	$ 37,099	$ 127,564	$ 112,744