Real Estate Facilities (Narrative) (Details) ft² in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021 USD ($) ft² storageFacility	Dec. 31, 2020 USD ($) ft² storageFacility	Dec. 31, 2019 USD ($) ft² storageFacility commercialFacility
Schedule Of Real Estate Facilities [Line Items]
Payments to acquire real estate	$ 5,047,106	$ 792,266	$ 437,758
Proceeds from sale of real estate investments	16,296	1,796	762
Gain on sale of real estate	13,683	1,493	341
Write-off of cancelled projects	0	$ 3,226	$ 0
Adjusted basis of real estate	15,800,000
Disposal of Real Estate Facilities
Schedule Of Real Estate Facilities [Line Items]
Gain on sale of real estate	$ 13,700
Acquisition of Self-Storage Facilities Other Investments
Schedule Of Real Estate Facilities [Line Items]
Number of operating self-storage facilities | storageFacility	232	62	44
Net rentable area acquired | ft²	21,830	5,100	3,100
Total cost of acquisition	$ 5,100,000	$ 792,300	$ 439,600
Payments to acquire real estate	5,000,000		437,800
Issuance of partnership units	68,200
Payments to acquire intangible assets	174,900	14,900	18,500
Liabilities assumed		3,800
Mortgage debt assumed			1,800
Newly Developed and Expansion Projects | Completed Developed and Expansion Project
Schedule Of Real Estate Facilities [Line Items]
Aggregate costs to develop and expand	$ 218,000	$ 138,700	$ 379,100
Addtional net rentable square feet | ft²	1,600	1,100	3,700
Acquisition of Commercial Facility
Schedule Of Real Estate Facilities [Line Items]
Number of operating self-storage facilities | commercialFacility			1
Net rentable area acquired | ft²			46