Quarterly report pursuant to Section 13 or 15(d)

EARNINGS PER SHARE - Narrative (Details)

v3.22.2
EARNINGS PER SHARE - Narrative (Details)
 3 Months Ended 6 Months Ended
Jun. 30, 2022
shares
Jun. 30, 2022
shares
NSA OP, LP And DownREIT Partnership | Subordinated performance units    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Unit conversion ratio   1
Minimum conversion period (in years)   2 years
NSA OP, LP | OP units    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Unit conversion ratio   1
Minimum conversion period (in years)   1 year
NSA OP, LP | LTIP units    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Unit conversion ratio   1
DownREIT Partnership | OP units    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Unit conversion ratio   1
Minimum conversion period (in years)   5 years
DownREIT Partnership | Subordinated performance units    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Unit conversion ratio   1
Minimum conversion period (in years)   5 years
LTIP units with vesting based on service or market condition    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Equity interests excluded from computation of diluted earnings per share (in shares)   411,448
LTIP units with vesting based on future acquisitions    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Equity interests excluded from computation of diluted earnings per share (in shares)   252,894
OP units, DownREIT OP units, Subordinated performance units, DownREIT subordinated performance units    
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]    
Equity interests excluded from computation of diluted earnings per share (in shares) 58,400,000 58,300,000