SHAREHOLDERS' EQUITY AND NONCONTROLLING INTERESTS - Equity Interests (Details) - shares	Sep. 30, 2024	Dec. 31, 2023
Partnership Subsidiaries
Noncontrolling Interest [Line Items]
Outstanding equity interest (in shares)	60,147,033	53,879,191
Series A-1 preferred units | NSA OP, LP
Noncontrolling Interest [Line Items]
Outstanding equity interest (in shares)	1,205,675	1,212,340
OP units | NSA OP, LP
Noncontrolling Interest [Line Items]
Outstanding equity interest (in shares)	52,301,412	37,635,683
OP units | DownREIT Partnership
Noncontrolling Interest [Line Items]
Outstanding equity interest (in shares)	5,769,214	2,120,491
Subordinated performance units | NSA OP, LP
Noncontrolling Interest [Line Items]
Outstanding equity interest (in shares)	0	7,991,271
Subordinated performance units | DownREIT Partnership
Noncontrolling Interest [Line Items]
Outstanding equity interest (in shares)	0	4,133,474
LTIP units | NSA OP, LP
Noncontrolling Interest [Line Items]
Outstanding equity interest (in shares)	870,732	785,932