EARNINGS PER SHARE - Narrative (Details)
|
12 Months Ended |
|
Dec. 31, 2015
unit / shares
shares
|
|---|
| NSA OP, LP [Member] | OP units [Member] |
|
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |
|
| Unit conversion ratio |
1
|
| DownREIT Partnership [Member] | OP units [Member] |
|
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |
|
| Unit conversion ratio |
1
|
| NSA OP, LP And DownREIT Partnership [Member] | OP units [Member] |
|
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |
|
| Minimum conversion period |
1 year
|
| NSA OP, LP And DownREIT Partnership [Member] | Subordinated performance units [Member] |
|
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |
|
| Unit conversion ratio |
1
|
| Minimum conversion period |
2 years
|
| Long-Term Incentive Plan Unit Based On Service [Member] |
|
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |
|
| Weighted average outstanding equity interests excluded from computation of earnings (in units) | shares |
236,265
|
| Long-Term Incentive Plan Unit Based On Future Acquisitions [Member] | Participating Regional Operator [Member] | Management [Member] |
|
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |
|
| Weighted average outstanding equity interests excluded from computation of earnings (in units) | shares |
423,800
|