SUBSEQUENT EVENTS - Debt (Details) (USD $) In Thousands, unless otherwise specified
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2 Months Ended |
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Jun. 05, 2015
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Mar. 31, 2015
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Loans Payable [Member] | Unsecured Term Loan [Member] |
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Extinguishment of Debt [Line Items] |
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Effective interest rate |
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5.18%us-gaap_DebtInstrumentInterestRateEffectivePercentage / us-gaap_DebtInstrumentAxis = nsa_UnsecuredTermLoanMember / us-gaap_ExtinguishmentOfDebtAxis = us-gaap_LoansPayableMember
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Mortgages [Member] | US Bank senior term loan [Member] |
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Extinguishment of Debt [Line Items] |
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Effective interest rate |
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2.58%us-gaap_DebtInstrumentInterestRateEffectivePercentage / us-gaap_DebtInstrumentAxis = nsa_SeniorTermLoanOneMember / us-gaap_ExtinguishmentOfDebtAxis = us-gaap_MortgagesMember
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Mortgages [Member] | US Bank senior term loan [Member] |
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Extinguishment of Debt [Line Items] |
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Effective interest rate |
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2.43%us-gaap_DebtInstrumentInterestRateEffectivePercentage / us-gaap_DebtInstrumentAxis = nsa_SeniorTermLoanTwoMember / us-gaap_ExtinguishmentOfDebtAxis = us-gaap_MortgagesMember
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Mortgages [Member] | Mezzanine loan [Member] |
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Extinguishment of Debt [Line Items] |
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Effective interest rate |
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9.65%us-gaap_DebtInstrumentInterestRateEffectivePercentage / us-gaap_DebtInstrumentAxis = nsa_MezzanineLoanMember / us-gaap_ExtinguishmentOfDebtAxis = us-gaap_MortgagesMember
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Line of Credit [Member] | Revolving line of credit [Member] |
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Extinguishment of Debt [Line Items] |
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Effective interest rate |
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2.78%us-gaap_DebtInstrumentInterestRateEffectivePercentage / us-gaap_CreditFacilityAxis = us-gaap_RevolvingCreditFacilityMember / us-gaap_ExtinguishmentOfDebtAxis = us-gaap_LineOfCreditMember
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Subsequent Event [Member] |
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Extinguishment of Debt [Line Items] |
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Extinguishment of debt, principal |
$ 229,800us-gaap_ExtinguishmentOfDebtAmount / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember
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Extinguishment of debt, prepayment penalty |
500nsa_ExtinguishmentOfDebtPrepaymentPenalty / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember
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Extinguishment of debt, write-off of debt issuance costs |
414us-gaap_WriteOffOfDeferredDebtIssuanceCost / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember
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Subsequent Event [Member] | Loans Payable [Member] | Unsecured Term Loan [Member] |
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Extinguishment of Debt [Line Items] |
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Extinguishment of debt, principal |
50,000us-gaap_ExtinguishmentOfDebtAmount / us-gaap_DebtInstrumentAxis = nsa_UnsecuredTermLoanMember / us-gaap_ExtinguishmentOfDebtAxis = us-gaap_LoansPayableMember / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember
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Extinguishment of debt, write-off of debt issuance costs |
219us-gaap_WriteOffOfDeferredDebtIssuanceCost / us-gaap_DebtInstrumentAxis = nsa_UnsecuredTermLoanMember / us-gaap_ExtinguishmentOfDebtAxis = us-gaap_LoansPayableMember / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember
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Subsequent Event [Member] | Mortgages [Member] | Variable Rate Mortgages [Member] |
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Extinguishment of Debt [Line Items] |
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Extinguishment of debt, principal |
83,500us-gaap_ExtinguishmentOfDebtAmount / us-gaap_DebtInstrumentAxis = nsa_VariableRateMortgagesMember / us-gaap_ExtinguishmentOfDebtAxis = us-gaap_MortgagesMember / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember
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Extinguishment of debt, prepayment penalty |
500nsa_ExtinguishmentOfDebtPrepaymentPenalty / us-gaap_DebtInstrumentAxis = nsa_VariableRateMortgagesMember / us-gaap_ExtinguishmentOfDebtAxis = us-gaap_MortgagesMember / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember
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Extinguishment of debt, write-off of debt issuance costs |
195us-gaap_WriteOffOfDeferredDebtIssuanceCost / us-gaap_DebtInstrumentAxis = nsa_VariableRateMortgagesMember / us-gaap_ExtinguishmentOfDebtAxis = us-gaap_MortgagesMember / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember
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Subsequent Event [Member] | Mortgages [Member] | US Bank senior term loan [Member] |
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Extinguishment of Debt [Line Items] |
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Extinguishment of debt, principal |
52,000us-gaap_ExtinguishmentOfDebtAmount / us-gaap_DebtInstrumentAxis = nsa_SeniorTermLoanOneMember / us-gaap_ExtinguishmentOfDebtAxis = us-gaap_MortgagesMember / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember
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Extinguishment of debt, write-off of debt issuance costs |
137us-gaap_WriteOffOfDeferredDebtIssuanceCost / us-gaap_DebtInstrumentAxis = nsa_SeniorTermLoanOneMember / us-gaap_ExtinguishmentOfDebtAxis = us-gaap_MortgagesMember / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember
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Subsequent Event [Member] | Mortgages [Member] | US Bank senior term loan [Member] |
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Extinguishment of Debt [Line Items] |
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Extinguishment of debt, principal |
6,500us-gaap_ExtinguishmentOfDebtAmount / us-gaap_DebtInstrumentAxis = nsa_SeniorTermLoanTwoMember / us-gaap_ExtinguishmentOfDebtAxis = us-gaap_MortgagesMember / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember
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Extinguishment of debt, write-off of debt issuance costs |
16us-gaap_WriteOffOfDeferredDebtIssuanceCost / us-gaap_DebtInstrumentAxis = nsa_SeniorTermLoanTwoMember / us-gaap_ExtinguishmentOfDebtAxis = us-gaap_MortgagesMember / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember
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Subsequent Event [Member] | Mortgages [Member] | Mezzanine loan [Member] |
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Extinguishment of Debt [Line Items] |
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Extinguishment of debt, principal |
25,000us-gaap_ExtinguishmentOfDebtAmount / us-gaap_DebtInstrumentAxis = nsa_MezzanineLoanMember / us-gaap_ExtinguishmentOfDebtAxis = us-gaap_MortgagesMember / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember
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Extinguishment of debt, prepayment penalty |
500nsa_ExtinguishmentOfDebtPrepaymentPenalty / us-gaap_DebtInstrumentAxis = nsa_MezzanineLoanMember / us-gaap_ExtinguishmentOfDebtAxis = us-gaap_MortgagesMember / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember
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Extinguishment of debt, write-off of debt issuance costs |
42us-gaap_WriteOffOfDeferredDebtIssuanceCost / us-gaap_DebtInstrumentAxis = nsa_MezzanineLoanMember / us-gaap_ExtinguishmentOfDebtAxis = us-gaap_MortgagesMember / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember
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Subsequent Event [Member] | Line of Credit [Member] | Revolving line of credit [Member] |
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Extinguishment of Debt [Line Items] |
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Extinguishment of debt, principal |
$ 96,300us-gaap_ExtinguishmentOfDebtAmount / us-gaap_CreditFacilityAxis = us-gaap_RevolvingCreditFacilityMember / us-gaap_ExtinguishmentOfDebtAxis = us-gaap_LineOfCreditMember / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember
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