DEBT FINANCING - Debt Summary (Details) (USD $) In Thousands, unless otherwise specified
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Mar. 31, 2015
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Dec. 31, 2014
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Debt Instrument [Line Items] |
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Debt financing |
$ 618,290us-gaap_DebtLongtermAndShorttermCombinedAmount
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$ 597,691us-gaap_DebtLongtermAndShorttermCombinedAmount
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Related Party Note [Member] |
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Debt Instrument [Line Items] |
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Debt financing |
4,054us-gaap_DebtLongtermAndShorttermCombinedAmount / us-gaap_DebtInstrumentAxis = nsa_RelatedPartyNoteMember
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0us-gaap_DebtLongtermAndShorttermCombinedAmount / us-gaap_DebtInstrumentAxis = nsa_RelatedPartyNoteMember
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Effective interest rate |
3.30%us-gaap_DebtInstrumentInterestRateEffectivePercentage / us-gaap_DebtInstrumentAxis = nsa_RelatedPartyNoteMember
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Line of Credit [Member] | Credit Facility [Member] | Revolving line of credit [Member] |
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Debt Instrument [Line Items] |
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Debt financing |
182,217us-gaap_DebtLongtermAndShorttermCombinedAmount / us-gaap_CreditFacilityAxis = us-gaap_RevolvingCreditFacilityMember / us-gaap_DebtInstrumentAxis = nsa_CreditFacilityMember / us-gaap_LongtermDebtTypeAxis = us-gaap_LineOfCreditMember
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166,217us-gaap_DebtLongtermAndShorttermCombinedAmount / us-gaap_CreditFacilityAxis = us-gaap_RevolvingCreditFacilityMember / us-gaap_DebtInstrumentAxis = nsa_CreditFacilityMember / us-gaap_LongtermDebtTypeAxis = us-gaap_LineOfCreditMember
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Effective interest rate |
2.78%us-gaap_DebtInstrumentInterestRateEffectivePercentage / us-gaap_CreditFacilityAxis = us-gaap_RevolvingCreditFacilityMember / us-gaap_DebtInstrumentAxis = nsa_CreditFacilityMember / us-gaap_LongtermDebtTypeAxis = us-gaap_LineOfCreditMember
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Line of Credit [Member] | Credit Facility [Member] | Term Loan [Member] |
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Debt Instrument [Line Items] |
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Debt financing |
144,558us-gaap_DebtLongtermAndShorttermCombinedAmount / us-gaap_CreditFacilityAxis = nsa_TermLoanMember / us-gaap_DebtInstrumentAxis = nsa_CreditFacilityMember / us-gaap_LongtermDebtTypeAxis = us-gaap_LineOfCreditMember
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144,558us-gaap_DebtLongtermAndShorttermCombinedAmount / us-gaap_CreditFacilityAxis = nsa_TermLoanMember / us-gaap_DebtInstrumentAxis = nsa_CreditFacilityMember / us-gaap_LongtermDebtTypeAxis = us-gaap_LineOfCreditMember
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Effective interest rate |
3.65%us-gaap_DebtInstrumentInterestRateEffectivePercentage / us-gaap_CreditFacilityAxis = nsa_TermLoanMember / us-gaap_DebtInstrumentAxis = nsa_CreditFacilityMember / us-gaap_LongtermDebtTypeAxis = us-gaap_LineOfCreditMember
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Loans Payable [Member] | Unsecured Term Loan [Member] |
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Debt Instrument [Line Items] |
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Debt financing |
50,000us-gaap_DebtLongtermAndShorttermCombinedAmount / us-gaap_DebtInstrumentAxis = nsa_UnsecuredTermLoanMember / us-gaap_LongtermDebtTypeAxis = us-gaap_LoansPayableMember
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50,000us-gaap_DebtLongtermAndShorttermCombinedAmount / us-gaap_DebtInstrumentAxis = nsa_UnsecuredTermLoanMember / us-gaap_LongtermDebtTypeAxis = us-gaap_LoansPayableMember
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Effective interest rate |
5.18%us-gaap_DebtInstrumentInterestRateEffectivePercentage / us-gaap_DebtInstrumentAxis = nsa_UnsecuredTermLoanMember / us-gaap_LongtermDebtTypeAxis = us-gaap_LoansPayableMember
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Mortgages [Member] | Fixed Rate Mortgages [Member] |
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Debt Instrument [Line Items] |
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Debt financing |
153,961us-gaap_DebtLongtermAndShorttermCombinedAmount / us-gaap_DebtInstrumentAxis = nsa_FixedRateMortgagesMember / us-gaap_LongtermDebtTypeAxis = us-gaap_MortgagesMember
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153,416us-gaap_DebtLongtermAndShorttermCombinedAmount / us-gaap_DebtInstrumentAxis = nsa_FixedRateMortgagesMember / us-gaap_LongtermDebtTypeAxis = us-gaap_MortgagesMember
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Effective interest rate |
4.07%us-gaap_DebtInstrumentInterestRateEffectivePercentage / us-gaap_DebtInstrumentAxis = nsa_FixedRateMortgagesMember / us-gaap_LongtermDebtTypeAxis = us-gaap_MortgagesMember
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Mortgages [Member] | Variable Rate Mortgages [Member] |
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Debt Instrument [Line Items] |
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Debt financing |
$ 83,500us-gaap_DebtLongtermAndShorttermCombinedAmount / us-gaap_DebtInstrumentAxis = nsa_VariableRateMortgagesMember / us-gaap_LongtermDebtTypeAxis = us-gaap_MortgagesMember
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$ 83,500us-gaap_DebtLongtermAndShorttermCombinedAmount / us-gaap_DebtInstrumentAxis = nsa_VariableRateMortgagesMember / us-gaap_LongtermDebtTypeAxis = us-gaap_MortgagesMember
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Effective interest rate |
4.69%us-gaap_DebtInstrumentInterestRateEffectivePercentage / us-gaap_DebtInstrumentAxis = nsa_VariableRateMortgagesMember / us-gaap_LongtermDebtTypeAxis = us-gaap_MortgagesMember
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