Schedule III - Real Estate and Accumulated Depreciation - Property Summary (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($) store
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	1,133
Debt	$ 1,294,423
Land Initial Cost	2,353,802
Building and Improvements Initial Cost	8,486,066
Adjustments and Costs to Land and Building Subsequent to Acquisition	1,296,634
Gross carrying amount - Land	2,356,746
Gross carrying amount - Building and improvements	9,779,756
Gross carrying amount - Total	12,136,502
Accumulated Depreciation	$ 2,138,524
Self storage facilities | AL
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	9
Debt	$ 5,687
Land Initial Cost	12,759
Building and Improvements Initial Cost	78,243
Adjustments and Costs to Land and Building Subsequent to Acquisition	4,164
Gross carrying amount - Land	12,759
Gross carrying amount - Building and improvements	82,407
Gross carrying amount - Total	95,166
Accumulated Depreciation	$ 12,590
Self storage facilities | AZ
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	25
Debt	$ 23,676
Land Initial Cost	37,192
Building and Improvements Initial Cost	150,772
Adjustments and Costs to Land and Building Subsequent to Acquisition	12,588
Gross carrying amount - Land	37,190
Gross carrying amount - Building and improvements	163,362
Gross carrying amount - Total	200,552
Accumulated Depreciation	$ 36,053
Self storage facilities | CA
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	177
Debt	$ 334,247
Land Initial Cost	665,423
Building and Improvements Initial Cost	1,394,380
Adjustments and Costs to Land and Building Subsequent to Acquisition	199,150
Gross carrying amount - Land	663,569
Gross carrying amount - Building and improvements	1,595,384
Gross carrying amount - Total	2,258,953
Accumulated Depreciation	$ 379,484
Self storage facilities | CO
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	17
Debt	$ 28,137
Land Initial Cost	17,224
Building and Improvements Initial Cost	81,144
Adjustments and Costs to Land and Building Subsequent to Acquisition	18,733
Gross carrying amount - Land	17,942
Gross carrying amount - Building and improvements	99,159
Gross carrying amount - Total	117,101
Accumulated Depreciation	$ 28,713
Self storage facilities | CT
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	7
Debt	$ 6,609
Land Initial Cost	9,789
Building and Improvements Initial Cost	61,688
Adjustments and Costs to Land and Building Subsequent to Acquisition	5,631
Gross carrying amount - Land	9,789
Gross carrying amount - Building and improvements	67,319
Gross carrying amount - Total	77,108
Accumulated Depreciation	$ 12,866
Self storage facilities | FL
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	112
Debt	$ 170,965
Land Initial Cost	203,643
Building and Improvements Initial Cost	869,142
Adjustments and Costs to Land and Building Subsequent to Acquisition	102,902
Gross carrying amount - Land	205,335
Gross carrying amount - Building and improvements	970,352
Gross carrying amount - Total	1,175,687
Accumulated Depreciation	$ 189,822
Self storage facilities | GA
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	67
Debt	$ 74,374
Land Initial Cost	89,898
Building and Improvements Initial Cost	455,894
Adjustments and Costs to Land and Building Subsequent to Acquisition	42,551
Gross carrying amount - Land	89,882
Gross carrying amount - Building and improvements	498,461
Gross carrying amount - Total	588,343
Accumulated Depreciation	$ 100,924
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	28,537
Building and Improvements Initial Cost	160,978
Adjustments and Costs to Land and Building Subsequent to Acquisition	14,085
Gross carrying amount - Land	28,537
Gross carrying amount - Building and improvements	175,063
Gross carrying amount - Total	203,600
Accumulated Depreciation	$ 38,133
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	20
Gross carrying amount - Land	4,047
Gross carrying amount - Building and improvements	25,255
Gross carrying amount - Total	29,302
Accumulated Depreciation	$ 162
Self storage facilities | IL
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	60
Debt	$ 16,627
Land Initial Cost	61,580
Building and Improvements Initial Cost	344,755
Adjustments and Costs to Land and Building Subsequent to Acquisition	38,447
Gross carrying amount - Land	61,033
Gross carrying amount - Building and improvements	383,749
Gross carrying amount - Total	444,782
Accumulated Depreciation	$ 62,487
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	494,469
Adjustments and Costs to Land and Building Subsequent to Acquisition	8,141
Gross carrying amount - Land	64,528
Gross carrying amount - Building and improvements	502,613
Gross carrying amount - Total	567,141
Accumulated Depreciation	$ 20,388
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	1,123
Gross carrying amount - Land	366
Gross carrying amount - Building and improvements	3,020
Gross carrying amount - Total	3,386
Accumulated Depreciation	$ 1,442
Self storage facilities | KY
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	13
Debt	$ 31,483
Land Initial Cost	8,531
Building and Improvements Initial Cost	77,872
Adjustments and Costs to Land and Building Subsequent to Acquisition	19,485
Gross carrying amount - Land	9,303
Gross carrying amount - Building and improvements	96,585
Gross carrying amount - Total	105,888
Accumulated Depreciation	$ 18,590
Self storage facilities | LA
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	10,005
Building and Improvements Initial Cost	51,934
Adjustments and Costs to Land and Building Subsequent to Acquisition	5,144
Gross carrying amount - Land	10,006
Gross carrying amount - Building and improvements	57,077
Gross carrying amount - Total	67,083
Accumulated Depreciation	$ 6,501
Self storage facilities | MA
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	47
Debt	$ 33,948
Land Initial Cost	77,617
Building and Improvements Initial Cost	276,254
Adjustments and Costs to Land and Building Subsequent to Acquisition	60,272
Gross carrying amount - Land	77,798
Gross carrying amount - Building and improvements	336,345
Gross carrying amount - Total	414,143
Accumulated Depreciation	$ 110,133
Self storage facilities | MD
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	35
Debt	$ 77,135
Land Initial Cost	109,414
Building and Improvements Initial Cost	345,585
Adjustments and Costs to Land and Building Subsequent to Acquisition	33,514
Gross carrying amount - Land	108,822
Gross carrying amount - Building and improvements	379,690
Gross carrying amount - Total	488,512
Accumulated Depreciation	$ 99,014
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	$ 5,486
Land Initial Cost	10,900
Building and Improvements Initial Cost	63,388
Adjustments and Costs to Land and Building Subsequent to Acquisition	5,498
Gross carrying amount - Land	10,900
Gross carrying amount - Building and improvements	68,886
Gross carrying amount - Total	79,786
Accumulated Depreciation	$ 11,008
Self storage facilities | MN
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	9,696
Building and Improvements Initial Cost	74,960
Adjustments and Costs to Land and Building Subsequent to Acquisition	6,537
Gross carrying amount - Land	9,696
Gross carrying amount - Building and improvements	81,497
Gross carrying amount - Total	91,193
Accumulated Depreciation	$ 7,755
Self storage facilities | MO
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	6
Debt	$ 0
Land Initial Cost	5,633
Building and Improvements Initial Cost	34,252
Adjustments and Costs to Land and Building Subsequent to Acquisition	7,499
Gross carrying amount - Land	5,591
Gross carrying amount - Building and improvements	41,793
Gross carrying amount - Total	47,384
Accumulated Depreciation	$ 8,587
Self storage facilities | MS
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	3
Debt	$ 0
Land Initial Cost	2,914
Building and Improvements Initial Cost	29,630
Adjustments and Costs to Land and Building Subsequent to Acquisition	1,410
Gross carrying amount - Land	2,914
Gross carrying amount - Building and improvements	31,040
Gross carrying amount - Total	33,954
Accumulated Depreciation	$ 4,105
Self storage facilities | NC
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	23
Debt	$ 0
Land Initial Cost	38,463
Building and Improvements Initial Cost	150,475
Adjustments and Costs to Land and Building Subsequent to Acquisition	12,017
Gross carrying amount - Land	38,461
Gross carrying amount - Building and improvements	162,494
Gross carrying amount - Total	200,955
Accumulated Depreciation	$ 22,883
Self storage facilities | NH
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	754
Building and Improvements Initial Cost	4,054
Adjustments and Costs to Land and Building Subsequent to Acquisition	1,401
Gross carrying amount - Land	817
Gross carrying amount - Building and improvements	5,392
Gross carrying amount - Total	6,209
Accumulated Depreciation	$ 2,881
Self storage facilities | NJ
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	64
Debt	$ 109,010
Land Initial Cost	142,724
Building and Improvements Initial Cost	651,442
Adjustments and Costs to Land and Building Subsequent to Acquisition	57,849
Gross carrying amount - Land	145,950
Gross carrying amount - Building and improvements	706,065
Gross carrying amount - Total	852,015
Accumulated Depreciation	$ 184,072
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	$ 18,648
Land Initial Cost	31,826
Building and Improvements Initial Cost	68,779
Adjustments and Costs to Land and Building Subsequent to Acquisition	5,978
Gross carrying amount - Land	31,826
Gross carrying amount - Building and improvements	74,758
Gross carrying amount - Total	106,584
Accumulated Depreciation	$ 14,760
Self storage facilities | NV
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	14
Debt	$ 30,597
Land Initial Cost	15,252
Building and Improvements Initial Cost	74,376
Adjustments and Costs to Land and Building Subsequent to Acquisition	7,085
Gross carrying amount - Land	15,252
Gross carrying amount - Building and improvements	81,461
Gross carrying amount - Total	96,713
Accumulated Depreciation	$ 17,259
Self storage facilities | NY
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	28
Debt	$ 13,807
Land Initial Cost	121,945
Building and Improvements Initial Cost	237,795
Adjustments and Costs to Land and Building Subsequent to Acquisition	46,207
Gross carrying amount - Land	122,680
Gross carrying amount - Building and improvements	283,267
Gross carrying amount - Total	405,947
Accumulated Depreciation	$ 85,218
Self storage facilities | OH
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	24
Debt	$ 11,374
Land Initial Cost	19,973
Building and Improvements Initial Cost	77,180
Adjustments and Costs to Land and Building Subsequent to Acquisition	10,995
Gross carrying amount - Land	19,973
Gross carrying amount - Building and improvements	88,175
Gross carrying amount - Total	108,148
Accumulated Depreciation	$ 18,509
Self storage facilities | OK
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	721
Building and Improvements Initial Cost	6,125
Adjustments and Costs to Land and Building Subsequent to Acquisition	0
Gross carrying amount - Land	721
Gross carrying amount - Building and improvements	6,125
Gross carrying amount - Total	6,846
Accumulated Depreciation	$ 65
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	$ 16,431
Land Initial Cost	15,066
Building and Improvements Initial Cost	68,044
Adjustments and Costs to Land and Building Subsequent to Acquisition	2,617
Gross carrying amount - Land	15,066
Gross carrying amount - Building and improvements	70,661
Gross carrying amount - Total	85,727
Accumulated Depreciation	$ 12,199
Self storage facilities | PA
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	21
Debt	$ 10,894
Land Initial Cost	39,704
Building and Improvements Initial Cost	203,360
Adjustments and Costs to Land and Building Subsequent to Acquisition	17,340
Gross carrying amount - Land	39,032
Gross carrying amount - Building and improvements	221,371
Gross carrying amount - Total	260,403
Accumulated Depreciation	$ 38,174
Self storage facilities | RI
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	2
Debt	$ 3,835
Land Initial Cost	3,191
Building and Improvements Initial Cost	6,926
Adjustments and Costs to Land and Building Subsequent to Acquisition	1,550
Gross carrying amount - Land	3,191
Gross carrying amount - Building and improvements	8,476
Gross carrying amount - Total	11,667
Accumulated Depreciation	$ 3,729
Self storage facilities | SC
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	23
Debt	$ 27,850
Land Initial Cost	36,617
Building and Improvements Initial Cost	148,900
Adjustments and Costs to Land and Building Subsequent to Acquisition	12,120
Gross carrying amount - Land	36,618
Gross carrying amount - Building and improvements	161,019
Gross carrying amount - Total	197,637
Accumulated Depreciation	$ 33,901
Self storage facilities | TN
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	22
Debt	$ 44,489
Land Initial Cost	35,981
Building and Improvements Initial Cost	151,674
Adjustments and Costs to Land and Building Subsequent to Acquisition	13,587
Gross carrying amount - Land	35,981
Gross carrying amount - Building and improvements	165,262
Gross carrying amount - Total	201,243
Accumulated Depreciation	$ 30,348
Self storage facilities | TX
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	111
Debt	$ 111,417
Land Initial Cost	205,385
Building and Improvements Initial Cost	760,041
Adjustments and Costs to Land and Building Subsequent to Acquisition	75,963
Gross carrying amount - Land	205,237
Gross carrying amount - Building and improvements	836,152
Gross carrying amount - Total	1,041,389
Accumulated Depreciation	$ 166,839
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	$ 16,670
Land Initial Cost	9,008
Building and Improvements Initial Cost	39,295
Adjustments and Costs to Land and Building Subsequent to Acquisition	3,615
Gross carrying amount - Land	9,008
Gross carrying amount - Building and improvements	42,910
Gross carrying amount - Total	51,918
Accumulated Depreciation	$ 13,949
Self storage facilities | VA
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	53
Debt	$ 58,133
Land Initial Cost	156,074
Building and Improvements Initial Cost	517,534
Adjustments and Costs to Land and Building Subsequent to Acquisition	32,574
Gross carrying amount - Land	156,075
Gross carrying amount - Building and improvements	550,107
Gross carrying amount - Total	706,182
Accumulated Depreciation	$ 108,891
Self storage facilities | DC
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Store Count | store	9
Debt	$ 5,030
Land Initial Cost	13,762
Building and Improvements Initial Cost	60,926
Adjustments and Costs to Land and Building Subsequent to Acquisition	12,572
Gross carrying amount - Land	13,764
Gross carrying amount - Building and improvements	73,496
Gross carrying amount - Total	87,260
Accumulated Depreciation	$ 16,483
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	$ 7,864
Land Initial Cost	14,394
Building and Improvements Initial Cost	18,172
Adjustments and Costs to Land and Building Subsequent to Acquisition	566
Gross carrying amount - Land	14,394
Gross carrying amount - Building and improvements	18,738
Gross carrying amount - Total	33,132
Accumulated Depreciation	3,383
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	207,609
Gross carrying amount - Land	0
Gross carrying amount - Building and improvements	207,609
Gross carrying amount - Total	207,609
Accumulated Depreciation	67,700
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	165,718
Adjustments and Costs to Land and Building Subsequent to Acquisition	0
Gross carrying amount - Land	0
Gross carrying amount - Building and improvements	165,718
Gross carrying amount - Total	165,718
Accumulated Depreciation	144,144
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	23,263
Building and Improvements Initial Cost	2,778
Adjustments and Costs to Land and Building Subsequent to Acquisition	51,836
Gross carrying amount - Land	22,693
Gross carrying amount - Building and improvements	55,184
Gross carrying amount - Total	77,877
Accumulated Depreciation	632
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	136,259
Gross carrying amount - Land	0
Gross carrying amount - Building and improvements	136,259
Gross carrying amount - Total	136,259
Accumulated Depreciation	$ 3,748