INVESTMENT ACTIVITY (Details) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended		12 Months Ended	21 Months Ended
	Aug. 31, 2023 USD ($)	Sep. 30, 2024 USD ($) facility	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($) facility	Sep. 30, 2023 USD ($)	Dec. 31, 2023 USD ($) facility	Sep. 30, 2024 USD ($) facility property
Self storage under construction
Self-storage facilities
Number of self-storage facilities | facility		2		2			2
Development costs		$ 18,600		$ 18,600			$ 18,600
Expected construction cost		45,700		$ 45,700			$ 45,700
Self Storage Facilities in New York and New Jersey
Self-storage facilities
Number of stores | property							2
2024 Acquisitions
Self-storage facilities
Number of self-storage facilities acquired | facility				2
Aggregate purchase price				$ 20,200
Aggregate acquisition price		22,000		22,000			$ 22,000
Intangible value of the in-place leases		$ 900		$ 900			$ 900
Estimated life		12 months		12 months			12 months
Amortization expense		$ 200		$ 600
Escrow deposit		$ 500		$ 500			$ 500
Number of facilities to be acquired | facility				2
Purchase Price				$ 20,200
2023 Acquisitions
Self-storage facilities
Number of self-storage facilities acquired | facility						1
Aggregate purchase price						$ 22,000
Intangible value of the in-place leases						2,000
Estimated life		12 months		12 months			12 months
Amortization expense		$ 500	$ 0	$ 1,500	$ 0
Purchase Price						$ 22,000
2023 Acquisitions | New Jersey
Self-storage facilities
Number of self-storage facilities acquired | facility						1
2023 Dispositions
Self-storage facilities
Aggregate sale price						$ 8,000
2023 Dispositions | LAACO
Self-storage facilities
Aggregate sale price						800
Gain (loss) from sale of real estate	$ (200)
2023 Dispositions | Illinois
Self-storage facilities
Proceeds from involuntary conversion, net						8,000
Gain on involuntary conversion, net						$ (4,800)
Cubesmart
Self-storage facilities
Ownership interest by Parent		99.50%		99.50%			99.50%