INVESTMENT IN UNCONSOLIDATED REAL ESTATE VENTURES - Condensed Financial Information (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
ASSETS
Self storage properties	$ 5,864,134	$ 5,792,174
Less accumulated depreciation	(1,051,638)	(874,359)
Self storage properties, net	4,812,496	4,917,815
Other assets	218,482	134,002
Total assets	5,354,462	5,931,811
LIABILITIES AND EQUITY
Debt financing	3,449,087	3,658,205
Equity	1,763,347	2,125,841	$ 2,389,014	$ 2,482,455
Total liabilities and equity	5,354,462	5,931,811
Equity Method Investment, Nonconsolidated Investee or Group of Investees | Joint Venture
ASSETS
Self storage properties	2,700,632	2,200,522
Less accumulated depreciation	(445,006)	(369,412)
Self storage properties, net	2,255,626	1,831,110
Other assets	43,513	37,826
Total assets	2,299,139	1,868,936
LIABILITIES AND EQUITY
Debt financing	1,213,169	1,003,223
Other liabilities	37,206	28,333
Equity	1,048,764	837,380
Total liabilities and equity	$ 2,299,139	$ 1,868,936