Schedule III - Real Estate and Accumulated Depreciation - Property Summary (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) store
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	1,905
Debt	$ 1,279,105
Land Initial Cost	4,885,859
Building and Improvements Initial Cost	20,652,053
Adjustments and Costs to Land and Building Subsequent to Acquisition	1,623,247
Gross carrying amount - Land	4,904,705
Gross carrying amount - Building and improvements	22,275,573
Gross carrying amount - Total	27,180,278
Accumulated Depreciation	$ 2,624,404
Self storage facilities | AL
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	37
Debt	$ 5,686
Land Initial Cost	52,358
Building and Improvements Initial Cost	380,499
Adjustments and Costs to Land and Building Subsequent to Acquisition	5,593
Gross carrying amount - Land	52,356
Gross carrying amount - Building and improvements	386,094
Gross carrying amount - Total	438,450
Accumulated Depreciation	$ 18,152
Self storage facilities | AZ
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	46
Debt	$ 22,349
Land Initial Cost	135,775
Building and Improvements Initial Cost	523,811
Adjustments and Costs to Land and Building Subsequent to Acquisition	14,566
Gross carrying amount - Land	135,774
Gross carrying amount - Building and improvements	538,378
Gross carrying amount - Total	674,152
Accumulated Depreciation	$ 44,843
Self storage facilities | CA
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	218
Debt	$ 328,992
Land Initial Cost	921,260
Building and Improvements Initial Cost	2,322,145
Adjustments and Costs to Land and Building Subsequent to Acquisition	250,704
Gross carrying amount - Land	919,806
Gross carrying amount - Building and improvements	2,574,302
Gross carrying amount - Total	3,494,108
Accumulated Depreciation	$ 436,926
Self storage facilities | CO
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	27
Debt	$ 26,374
Land Initial Cost	49,985
Building and Improvements Initial Cost	192,497
Adjustments and Costs to Land and Building Subsequent to Acquisition	20,004
Gross carrying amount - Land	50,703
Gross carrying amount - Building and improvements	211,783
Gross carrying amount - Total	262,486
Accumulated Depreciation	$ 33,009
Self storage facilities | CT
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	23
Debt	$ 6,399
Land Initial Cost	43,453
Building and Improvements Initial Cost	373,628
Adjustments and Costs to Land and Building Subsequent to Acquisition	6,530
Gross carrying amount - Land	43,452
Gross carrying amount - Building and improvements	380,158
Gross carrying amount - Total	423,610
Accumulated Depreciation	$ 18,276
Self storage facilities | FL
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	245
Debt	$ 167,386
Land Initial Cost	672,426
Building and Improvements Initial Cost	2,894,604
Adjustments and Costs to Land and Building Subsequent to Acquisition	122,780
Gross carrying amount - Land	674,576
Gross carrying amount - Building and improvements	3,015,234
Gross carrying amount - Total	3,689,810
Accumulated Depreciation	$ 239,687
Self storage facilities | GA
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	119
Debt	$ 78,837
Land Initial Cost	303,954
Building and Improvements Initial Cost	1,179,911
Adjustments and Costs to Land and Building Subsequent to Acquisition	47,713
Gross carrying amount - Land	303,941
Gross carrying amount - Building and improvements	1,227,636
Gross carrying amount - Total	1,531,577
Accumulated Depreciation	$ 123,363
Self storage facilities | HI
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	14
Debt	$ 0
Land Initial Cost	29,836
Building and Improvements Initial Cost	160,978
Adjustments and Costs to Land and Building Subsequent to Acquisition	22,962
Gross carrying amount - Land	29,836
Gross carrying amount - Building and improvements	183,939
Gross carrying amount - Total	213,775
Accumulated Depreciation	$ 43,351
Self storage facilities | ID
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	2
Debt	$ 0
Land Initial Cost	4,047
Building and Improvements Initial Cost	25,235
Adjustments and Costs to Land and Building Subsequent to Acquisition	59
Gross carrying amount - Land	4,047
Gross carrying amount - Building and improvements	25,294
Gross carrying amount - Total	29,341
Accumulated Depreciation	$ 812
Self storage facilities | IL
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	105
Debt	$ 16,231
Land Initial Cost	210,472
Building and Improvements Initial Cost	1,107,463
Adjustments and Costs to Land and Building Subsequent to Acquisition	43,952
Gross carrying amount - Land	209,924
Gross carrying amount - Building and improvements	1,151,964
Gross carrying amount - Total	1,361,888
Accumulated Depreciation	$ 82,109
Self storage facilities | IN
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	91
Debt	$ 0
Land Initial Cost	64,531
Building and Improvements Initial Cost	494,467
Adjustments and Costs to Land and Building Subsequent to Acquisition	14,626
Gross carrying amount - Land	64,875
Gross carrying amount - Building and improvements	524,169
Gross carrying amount - Total	589,044
Accumulated Depreciation	$ 34,445
Self storage facilities | KS
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	1
Debt	$ 0
Land Initial Cost	366
Building and Improvements Initial Cost	1,897
Adjustments and Costs to Land and Building Subsequent to Acquisition	1,150
Gross carrying amount - Land	366
Gross carrying amount - Building and improvements	3,047
Gross carrying amount - Total	3,413
Accumulated Depreciation	$ 1,555
Self storage facilities | KY
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	15
Debt	$ 30,470
Land Initial Cost	10,026
Building and Improvements Initial Cost	88,389
Adjustments and Costs to Land and Building Subsequent to Acquisition	21,129
Gross carrying amount - Land	10,799
Gross carrying amount - Building and improvements	108,745
Gross carrying amount - Total	119,544
Accumulated Depreciation	$ 21,462
Self storage facilities | LA
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	10
Debt	$ 0
Land Initial Cost	16,673
Building and Improvements Initial Cost	126,604
Adjustments and Costs to Land and Building Subsequent to Acquisition	5,591
Gross carrying amount - Land	16,674
Gross carrying amount - Building and improvements	132,194
Gross carrying amount - Total	148,868
Accumulated Depreciation	$ 8,844
Self storage facilities | MA
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	64
Debt	$ 39,808
Land Initial Cost	120,291
Building and Improvements Initial Cost	534,152
Adjustments and Costs to Land and Building Subsequent to Acquisition	65,286
Gross carrying amount - Land	120,472
Gross carrying amount - Building and improvements	599,257
Gross carrying amount - Total	719,729
Accumulated Depreciation	$ 123,019
Self storage facilities | MD
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	44
Debt	$ 74,081
Land Initial Cost	157,195
Building and Improvements Initial Cost	450,952
Adjustments and Costs to Land and Building Subsequent to Acquisition	36,025
Gross carrying amount - Land	156,605
Gross carrying amount - Building and improvements	487,567
Gross carrying amount - Total	644,172
Accumulated Depreciation	$ 111,043
Self storage facilities | ME
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	5
Debt	$ 0
Land Initial Cost	2,352
Building and Improvements Initial Cost	86,339
Adjustments and Costs to Land and Building Subsequent to Acquisition	195
Gross carrying amount - Land	2,352
Gross carrying amount - Building and improvements	86,534
Gross carrying amount - Total	88,886
Accumulated Depreciation	$ 926
Self storage facilities | MI
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	8
Debt	$ 4,301
Land Initial Cost	10,900
Building and Improvements Initial Cost	63,388
Adjustments and Costs to Land and Building Subsequent to Acquisition	6,630
Gross carrying amount - Land	10,900
Gross carrying amount - Building and improvements	70,018
Gross carrying amount - Total	80,918
Accumulated Depreciation	$ 13,061
Self storage facilities | MN
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	8
Debt	$ 0
Land Initial Cost	14,925
Building and Improvements Initial Cost	104,513
Adjustments and Costs to Land and Building Subsequent to Acquisition	6,940
Gross carrying amount - Land	14,925
Gross carrying amount - Building and improvements	111,453
Gross carrying amount - Total	126,378
Accumulated Depreciation	$ 10,240
Self storage facilities | MO
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	28
Debt	$ 0
Land Initial Cost	31,800
Building and Improvements Initial Cost	347,070
Adjustments and Costs to Land and Building Subsequent to Acquisition	8,250
Gross carrying amount - Land	31,758
Gross carrying amount - Building and improvements	355,362
Gross carrying amount - Total	387,120
Accumulated Depreciation	$ 13,743
Self storage facilities | MS
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	7
Debt	$ 0
Land Initial Cost	9,053
Building and Improvements Initial Cost	82,098
Adjustments and Costs to Land and Building Subsequent to Acquisition	1,977
Gross carrying amount - Land	9,052
Gross carrying amount - Building and improvements	84,076
Gross carrying amount - Total	93,128
Accumulated Depreciation	$ 5,559
Self storage facilities | NC
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	52
Debt	$ 0
Land Initial Cost	93,492
Building and Improvements Initial Cost	557,728
Adjustments and Costs to Land and Building Subsequent to Acquisition	14,431
Gross carrying amount - Land	93,489
Gross carrying amount - Building and improvements	572,161
Gross carrying amount - Total	665,650
Accumulated Depreciation	$ 32,134
Self storage facilities | NH
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	17
Debt	$ 0
Land Initial Cost	50,952
Building and Improvements Initial Cost	195,719
Adjustments and Costs to Land and Building Subsequent to Acquisition	1,735
Gross carrying amount - Land	51,015
Gross carrying amount - Building and improvements	197,391
Gross carrying amount - Total	248,406
Accumulated Depreciation	$ 5,097
Self storage facilities | NJ
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	88
Debt	$ 99,207
Land Initial Cost	308,001
Building and Improvements Initial Cost	1,071,004
Adjustments and Costs to Land and Building Subsequent to Acquisition	70,630
Gross carrying amount - Land	313,354
Gross carrying amount - Building and improvements	1,136,281
Gross carrying amount - Total	1,449,635
Accumulated Depreciation	$ 209,349
Self storage facilities | NM
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	11
Debt	$ 25,153
Land Initial Cost	31,826
Building and Improvements Initial Cost	68,779
Adjustments and Costs to Land and Building Subsequent to Acquisition	6,909
Gross carrying amount - Land	31,826
Gross carrying amount - Building and improvements	75,689
Gross carrying amount - Total	107,515
Accumulated Depreciation	$ 17,000
Self storage facilities | NV
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	33
Debt	$ 30,458
Land Initial Cost	97,497
Building and Improvements Initial Cost	469,028
Adjustments and Costs to Land and Building Subsequent to Acquisition	9,504
Gross carrying amount - Land	97,497
Gross carrying amount - Building and improvements	478,532
Gross carrying amount - Total	576,029
Accumulated Depreciation	$ 23,846
Self storage facilities | NY
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	79
Debt	$ 12,895
Land Initial Cost	340,256
Building and Improvements Initial Cost	1,195,359
Adjustments and Costs to Land and Building Subsequent to Acquisition	66,207
Gross carrying amount - Land	340,991
Gross carrying amount - Building and improvements	1,260,831
Gross carrying amount - Total	1,601,822
Accumulated Depreciation	$ 105,190
Self storage facilities | OH
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	50
Debt	$ 10,140
Land Initial Cost	71,460
Building and Improvements Initial Cost	388,236
Adjustments and Costs to Land and Building Subsequent to Acquisition	13,917
Gross carrying amount - Land	71,459
Gross carrying amount - Building and improvements	402,154
Gross carrying amount - Total	473,613
Accumulated Depreciation	$ 24,721
Self storage facilities | OK
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	4
Debt	$ 0
Land Initial Cost	3,917
Building and Improvements Initial Cost	28,534
Adjustments and Costs to Land and Building Subsequent to Acquisition	159
Gross carrying amount - Land	3,917
Gross carrying amount - Building and improvements	28,693
Gross carrying amount - Total	32,610
Accumulated Depreciation	$ 429
Self storage facilities | OR
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	8
Debt	$ 23,904
Land Initial Cost	15,066
Building and Improvements Initial Cost	68,044
Adjustments and Costs to Land and Building Subsequent to Acquisition	2,938
Gross carrying amount - Land	15,066
Gross carrying amount - Building and improvements	70,982
Gross carrying amount - Total	86,048
Accumulated Depreciation	$ 14,126
Self storage facilities | PA
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	31
Debt	$ 10,635
Land Initial Cost	57,671
Building and Improvements Initial Cost	356,325
Adjustments and Costs to Land and Building Subsequent to Acquisition	29,609
Gross carrying amount - Land	56,997
Gross carrying amount - Building and improvements	386,607
Gross carrying amount - Total	443,604
Accumulated Depreciation	$ 46,425
Self storage facilities | RI
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	6
Debt	$ 3,712
Land Initial Cost	6,132
Building and Improvements Initial Cost	55,033
Adjustments and Costs to Land and Building Subsequent to Acquisition	1,793
Gross carrying amount - Land	6,131
Gross carrying amount - Building and improvements	56,827
Gross carrying amount - Total	62,958
Accumulated Depreciation	$ 4,517
Self storage facilities | SC
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	40
Debt	$ 27,701
Land Initial Cost	65,032
Building and Improvements Initial Cost	385,333
Adjustments and Costs to Land and Building Subsequent to Acquisition	13,408
Gross carrying amount - Land	65,036
Gross carrying amount - Building and improvements	398,737
Gross carrying amount - Total	463,773
Accumulated Depreciation	$ 41,190
Self storage facilities | TN
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	29
Debt	$ 44,491
Land Initial Cost	50,603
Building and Improvements Initial Cost	252,731
Adjustments and Costs to Land and Building Subsequent to Acquisition	15,296
Gross carrying amount - Land	50,603
Gross carrying amount - Building and improvements	268,027
Gross carrying amount - Total	318,630
Accumulated Depreciation	$ 36,356
Self storage facilities | TX
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	241
Debt	$ 104,794
Land Initial Cost	534,804
Building and Improvements Initial Cost	2,603,707
Adjustments and Costs to Land and Building Subsequent to Acquisition	97,822
Gross carrying amount - Land	534,655
Gross carrying amount - Building and improvements	2,701,678
Gross carrying amount - Total	3,236,333
Accumulated Depreciation	$ 212,009
Self storage facilities | UT
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	10
Debt	$ 16,265
Land Initial Cost	9,008
Building and Improvements Initial Cost	39,295
Adjustments and Costs to Land and Building Subsequent to Acquisition	9,775
Gross carrying amount - Land	9,008
Gross carrying amount - Building and improvements	49,070
Gross carrying amount - Total	58,078
Accumulated Depreciation	$ 15,445
Self storage facilities | VA
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	73
Debt	$ 56,422
Land Initial Cost	198,998
Building and Improvements Initial Cost	842,848
Adjustments and Costs to Land and Building Subsequent to Acquisition	37,952
Gross carrying amount - Land	198,998
Gross carrying amount - Building and improvements	880,800
Gross carrying amount - Total	1,079,798
Accumulated Depreciation	$ 127,878
Self storage facilities | WA
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	14
Debt	$ 4,874
Land Initial Cost	51,011
Building and Improvements Initial Cost	147,943
Adjustments and Costs to Land and Building Subsequent to Acquisition	13,780
Gross carrying amount - Land	51,013
Gross carrying amount - Building and improvements	161,720
Gross carrying amount - Total	212,733
Accumulated Depreciation	$ 19,542
Self storage facilities | WI
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	1
Debt	$ 0
Land Initial Cost	1,076
Building and Improvements Initial Cost	16,054
Adjustments and Costs to Land and Building Subsequent to Acquisition	70
Gross carrying amount - Land	1,076
Gross carrying amount - Building and improvements	16,123
Gross carrying amount - Total	17,199
Accumulated Depreciation	$ 173
Self storage facilities | DC
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	1
Debt	$ 7,540
Land Initial Cost	14,394
Building and Improvements Initial Cost	18,172
Adjustments and Costs to Land and Building Subsequent to Acquisition	634
Gross carrying amount - Land	14,394
Gross carrying amount - Building and improvements	18,806
Gross carrying amount - Total	33,200
Accumulated Depreciation	3,904
Other corporate assets
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Debt	0
Land Initial Cost	0
Building and Improvements Initial Cost	0
Adjustments and Costs to Land and Building Subsequent to Acquisition	245,910
Gross carrying amount - Land	0
Gross carrying amount - Building and improvements	245,910
Gross carrying amount - Total	245,910
Accumulated Depreciation	92,553
Intangible tenant relationships and lease rights
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Debt	0
Land Initial Cost	0
Building and Improvements Initial Cost	348,762
Adjustments and Costs to Land and Building Subsequent to Acquisition	0
Gross carrying amount - Land	0
Gross carrying amount - Building and improvements	348,762
Gross carrying amount - Total	348,762
Accumulated Depreciation	204,135
Construction in Progress/Undeveloped Land
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Debt	0
Land Initial Cost	22,985
Building and Improvements Initial Cost	2,779
Adjustments and Costs to Land and Building Subsequent to Acquisition	124,265
Gross carrying amount - Land	34,987
Gross carrying amount - Building and improvements	118,745
Gross carrying amount - Total	153,732
Accumulated Depreciation	0
Right of use asset - finance lease
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Debt	0
Land Initial Cost	0
Building and Improvements Initial Cost	0
Adjustments and Costs to Land and Building Subsequent to Acquisition	143,841
Gross carrying amount - Land	0
Gross carrying amount - Building and improvements	143,843
Gross carrying amount - Total	143,843
Accumulated Depreciation	$ 3,960