INVESTMENT IN UNCONSOLIDATED REAL ESTATE VENTURES - Condensed Financial Position (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
ASSETS
Real Estate Investment Property, at Cost	$ 5,814,854	$ 5,864,134
Less accumulated depreciation	(1,213,537)	(1,051,638)
Self storage properties, net	4,601,317	4,812,496
Other assets	185,403	218,482
Total assets	5,080,115	5,354,462
LIABILITIES AND EQUITY
Debt financing	3,405,102	3,449,087
Equity	1,533,783	1,763,347	$ 2,125,841	$ 2,389,014
Total liabilities and equity	5,080,115	5,354,462
Equity Method Investment, Nonconsolidated Investee or Group of Investees | Joint Venture
ASSETS
Real Estate Investment Property, at Cost	2,762,740	2,700,632
Less accumulated depreciation	(525,006)	(445,006)
Self storage properties, net	2,237,734	2,255,626
Other assets	35,836	43,513
Total assets	2,273,570	2,299,139
LIABILITIES AND EQUITY
Debt financing	1,214,325	1,213,169
Other liabilities	33,068	37,206
Equity	1,026,177	1,048,764
Total liabilities and equity	$ 2,273,570	$ 2,299,139