v3.26.1
SHAREHOLDERS' EQUITY AND NONCONTROLLING INTERESTS - Narrative (Details) - USD ($)
$ / shares in Units, $ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Dec. 31, 2025
Nov. 19, 2024
Nov. 14, 2024
Dec. 01, 2023
Jul. 11, 2022
Class of Stock [Line Items]              
Preferred shares of beneficial interest, outstanding (in shares) 14,801,345   14,704,845        
Authorized amount         $ 350.0 $ 275.0 $ 400.0
Remaining authorized, amount $ 350.3            
Common Shares              
Class of Stock [Line Items]              
Redemptions of OP units (in shares) 32,741 93,661          
Prior Sales Agreement              
Class of Stock [Line Items]              
Value of common and preferred shares authorized under ATM program       $ 400.0      
At The Market Program              
Class of Stock [Line Items]              
Value of remaining available offered shares $ 400.0            
Series A Preferred Shares              
Class of Stock [Line Items]              
Preferred shares of beneficial interest, outstanding (in shares) 9,133,217            
NSA OP, LP | Series A-1 preferred units              
Class of Stock [Line Items]              
Preferred share/unit dividend rate (as a percent) 6.00%            
Preferred units cash redemption price (in dollars per share) $ 25.00            
Unit conversion ratio 1            
Minimum conversion period (in years) 10 years            
NSA OP, LP | OP units              
Class of Stock [Line Items]              
Redemptions of OP units (in shares) 302,615            
Unit conversion ratio 1            
Minimum conversion period (in years) 1 year            
NSA OP, LP | OP units | Common Shares              
Class of Stock [Line Items]              
Redemptions of OP units (in shares) 32,741            
NSA OP, LP | LTIP units              
Class of Stock [Line Items]              
Unit conversion ratio 1            
Conversion of units (in shares) 88,957            
Issuance of preferred shares upon redemption of preferred units (in shares) 88,957            
NSA OP, LP | Class B Unit | Retirement of Northwest              
Class of Stock [Line Items]              
Issuance of preferred shares upon redemption of preferred units (in shares) 171,339            
DownREIT Partnership | OP units              
Class of Stock [Line Items]              
Unit conversion ratio 1            
Minimum conversion period (in years) 5 years            
Series A Cumulative Redeemable Preferred Shares of Beneficial Interest, par value $0.01 per share              
Class of Stock [Line Items]              
Preferred share/unit dividend rate (as a percent) 6.00%            
Preferred dividends in arrears (in dollars per share) $ 1.50            
Series A Cumulative Redeemable Preferred Shares of Beneficial Interest, par value $0.01 per share | Series A-1 preferred units              
Class of Stock [Line Items]              
Preferred share/unit dividend rate (as a percent) 6.00%            
Series A Cumulative Redeemable Preferred Shares of Beneficial Interest, par value $0.01 per share | NSA OP, LP              
Class of Stock [Line Items]              
Preferred units cash redemption price (in dollars per share) $ 25.00            
Series A Cumulative Redeemable Preferred Shares of Beneficial Interest, par value $0.01 per share | NSA OP, LP | Series A Preferred Shares              
Class of Stock [Line Items]              
Redemptions of OP units (in shares) 96,500            
Common Shares of Beneficial Interest, $0.01 par value per share | At The Market Program              
Class of Stock [Line Items]              
Sale of stock, number of shares issued in transaction (in shares) 0