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EARNINGS PER SHARE - Weighted Average Outstanding Equity Interests (Details)
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3 Months Ended |
0 Months Ended |
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Mar. 31, 2015
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Mar. 31, 2014
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Apr. 01, 2014
property
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| Partnership Subsidiaries [Member] |
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|
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| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |
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|
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| Weighted average outstanding equity interests excluded from computation of earnings (in units) |
35,826,094us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
/ dei_LegalEntityAxis
= nsa_PartnershipSubsidiariesMember
|
15,687,877us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
/ dei_LegalEntityAxis
= nsa_PartnershipSubsidiariesMember
|
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| NSA Predecessor [Member] |
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| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |
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| Number of properties contributed to partnership |
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65nsa_NumberofPropertiesContributed
/ dei_LegalEntityAxis
= nsa_NSAPredecessorMember
|
| Number of entities under common control |
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2nsa_NumberofEntitiesUnderCommonControl
/ dei_LegalEntityAxis
= nsa_NSAPredecessorMember
|
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| OP units [Member] | NSA OP, LP [Member] |
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|
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| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |
|
|
|
| Weighted average outstanding equity interests excluded from computation of earnings (in units) |
19,205,125us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= nsa_ClassAUnitsMember
/ dei_LegalEntityAxis
= nsa_NSAOPLPMember
|
9,262,624us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= nsa_ClassAUnitsMember
/ dei_LegalEntityAxis
= nsa_NSAOPLPMember
|
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| OP units [Member] | DownREIT Partnership [Member] |
|
|
|
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |
|
|
|
| Weighted average outstanding equity interests excluded from computation of earnings (in units) |
1,386,143us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= nsa_ClassAUnitsMember
/ dei_LegalEntityAxis
= nsa_DownREITPartnershipMember
|
0us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= nsa_ClassAUnitsMember
/ dei_LegalEntityAxis
= nsa_DownREITPartnershipMember
|
|
| OP units [Member] | NSA Predecessor [Member] |
|
|
|
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |
|
|
|
| Weighted average outstanding equity interests excluded from computation of earnings (in units) |
|
2,060,711us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= nsa_ClassAUnitsMember
/ dei_LegalEntityAxis
= nsa_NSAPredecessorMember
|
|
| Subordinated performance units [Member] | NSA OP, LP [Member] |
|
|
|
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |
|
|
|
| Weighted average outstanding equity interests excluded from computation of earnings (in units) |
8,886,097us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= nsa_ClassBUnitMember
/ dei_LegalEntityAxis
= nsa_NSAOPLPMember
|
4,335,093us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= nsa_ClassBUnitMember
/ dei_LegalEntityAxis
= nsa_NSAOPLPMember
|
|
| Subordinated performance units [Member] | DownREIT Partnership [Member] |
|
|
|
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |
|
|
|
| Weighted average outstanding equity interests excluded from computation of earnings (in units) |
3,636,089us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= nsa_ClassBUnitMember
/ dei_LegalEntityAxis
= nsa_DownREITPartnershipMember
|
0us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= nsa_ClassBUnitMember
/ dei_LegalEntityAxis
= nsa_DownREITPartnershipMember
|
|
| Subordinated performance units [Member] | NSA Predecessor [Member] |
|
|
|
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |
|
|
|
| Weighted average outstanding equity interests excluded from computation of earnings (in units) |
|
1,464,782us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= nsa_ClassBUnitMember
/ dei_LegalEntityAxis
= nsa_NSAPredecessorMember
|
|
| LTIP units [Member] | NSA OP, LP [Member] |
|
|
|
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |
|
|
|
| Weighted average outstanding equity interests excluded from computation of earnings (in units) |
2,712,640us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= nsa_LongTermIncentivePlanUnitMember
/ dei_LegalEntityAxis
= nsa_NSAOPLPMember
|
2,090,160us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= nsa_LongTermIncentivePlanUnitMember
/ dei_LegalEntityAxis
= nsa_NSAOPLPMember
|
|
| LTIP units [Member] | Participating Regional Operator [Member] |
|
|
|
| Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |
|
|
|
| Weighted average outstanding equity interests excluded from computation of earnings (in units) |
522,900us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= nsa_LongTermIncentivePlanUnitMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= nsa_ParticipatingRegionalOperatorMember
|
902,870us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
/ us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis
= nsa_LongTermIncentivePlanUnitMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= nsa_ParticipatingRegionalOperatorMember
|
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