FAIR VALUE MEASUREMENTS - Interest Swap Derivatives (Details) (Interest Rate Swap [Member], Level 2 [Member], USD $)
In Thousands, unless otherwise specified |
3 Months Ended | |
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Mar. 31, 2015
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Mar. 31, 2014
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Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis [Roll Forward] | ||
Fair value at beginning of period | $ (1,072)nsa_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasis | $ 70nsa_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasis |
Unrealized losses included in interest expense | (121)nsa_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisGainLossIncludedInEarnings | (6)nsa_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisGainLossIncludedInEarnings |
Losses on interest rate swaps reclassified into interest expense from accumulated other comprehensive loss | 385nsa_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisGainLossIncludedInEarningsReclassificationFromAOCICurrentPeriod | |
Unrealized losses included in accumulated other comprehensive loss | (1,166)nsa_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisGainLossIncludedInOtherComprehensiveIncomeLoss | |
Fair value of end of period | (1,974)nsa_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasis | 64nsa_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasis |
Designated as Hedging Instrument [Member] | ||
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis [Roll Forward] | ||
Fair value at beginning of period |
(865)nsa_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasis / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_InterestRateSwapMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_HedgingDesignationAxis = us-gaap_DesignatedAsHedgingInstrumentMember |
0nsa_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasis / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_InterestRateSwapMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_HedgingDesignationAxis = us-gaap_DesignatedAsHedgingInstrumentMember |
Unrealized losses included in interest expense |
0nsa_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisGainLossIncludedInEarnings / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_InterestRateSwapMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_HedgingDesignationAxis = us-gaap_DesignatedAsHedgingInstrumentMember |
0nsa_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisGainLossIncludedInEarnings / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_InterestRateSwapMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_HedgingDesignationAxis = us-gaap_DesignatedAsHedgingInstrumentMember |
Losses on interest rate swaps reclassified into interest expense from accumulated other comprehensive loss |
385nsa_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisGainLossIncludedInEarningsReclassificationFromAOCICurrentPeriod / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_InterestRateSwapMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_HedgingDesignationAxis = us-gaap_DesignatedAsHedgingInstrumentMember |
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Unrealized losses included in accumulated other comprehensive loss |
(1,166)nsa_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_InterestRateSwapMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_HedgingDesignationAxis = us-gaap_DesignatedAsHedgingInstrumentMember |
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Fair value of end of period |
(1,646)nsa_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasis / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_InterestRateSwapMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_HedgingDesignationAxis = us-gaap_DesignatedAsHedgingInstrumentMember |
0nsa_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasis / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_InterestRateSwapMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_HedgingDesignationAxis = us-gaap_DesignatedAsHedgingInstrumentMember |
Not Designated as Hedging Instrument [Member] | ||
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis [Roll Forward] | ||
Fair value at beginning of period |
(207)nsa_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasis / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_InterestRateSwapMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_HedgingDesignationAxis = us-gaap_NondesignatedMember |
70nsa_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasis / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_InterestRateSwapMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_HedgingDesignationAxis = us-gaap_NondesignatedMember |
Unrealized losses included in interest expense |
(121)nsa_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisGainLossIncludedInEarnings / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_InterestRateSwapMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_HedgingDesignationAxis = us-gaap_NondesignatedMember |
(6)nsa_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisGainLossIncludedInEarnings / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_InterestRateSwapMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_HedgingDesignationAxis = us-gaap_NondesignatedMember |
Losses on interest rate swaps reclassified into interest expense from accumulated other comprehensive loss |
0nsa_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisGainLossIncludedInEarningsReclassificationFromAOCICurrentPeriod / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_InterestRateSwapMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_HedgingDesignationAxis = us-gaap_NondesignatedMember |
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Unrealized losses included in accumulated other comprehensive loss |
0nsa_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasisGainLossIncludedInOtherComprehensiveIncomeLoss / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_InterestRateSwapMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_HedgingDesignationAxis = us-gaap_NondesignatedMember |
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Fair value of end of period |
$ (328)nsa_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasis / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_InterestRateSwapMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_HedgingDesignationAxis = us-gaap_NondesignatedMember |
$ 64nsa_FairValueNetDerivativeAssetLiabilityMeasuredOnRecurringBasis / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_InterestRateSwapMember / us-gaap_FairValueByFairValueHierarchyLevelAxis = us-gaap_FairValueInputsLevel2Member / us-gaap_HedgingDesignationAxis = us-gaap_NondesignatedMember |
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Fair Value, Net Derivative Asset (Liability) Measured On Recurring Basis No definition available.
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Fair Value, Net Derivative Asset (Liability) Measured On Recurring Basis, Gain (Loss) Included In Earnings No definition available.
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Fair Value, Net Derivative Asset (Liability) Measured On Recurring Basis, Gain (Loss) Included In Earnings, Reclassification From AOCI, Current Period No definition available.
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Fair Value, Net Derivative Asset (Liability) Measured On Recurring Basis, Gain (Loss) Included In Other Comprehensive Income (Loss) No definition available.
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