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Investments (Schedule of Continuous Losses) (Details) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]    
Less than 12 Months, Fair Value $ 9,167us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue $ 29,355us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
Less than 12 Months, Gross Unrealized Losses 374nsec_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAggregateLossesI 1,796nsec_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAggregateLossesI
12 Months or Longer, Fair Value 9,061us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue 4,934us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue
12 Months or Longer, Gross Unrealized Losses 477nsec_AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLossesI 792nsec_AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLossesI
Total Fair Value 18,228us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue 34,289us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue
Total Gross Unrealized Losses 851nsec_AvailableForSaleSecuritiesGrossUnrealizedLoss1 2,588nsec_AvailableForSaleSecuritiesGrossUnrealizedLoss1
Total Securities in a Loss Position 44us-gaap_AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositions1 80us-gaap_AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositions1
Corporate Debt Securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Less than 12 Months, Fair Value 6,306us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_CorporateDebtSecuritiesMember
10,589us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_CorporateDebtSecuritiesMember
Less than 12 Months, Gross Unrealized Losses 364nsec_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAggregateLossesI
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_CorporateDebtSecuritiesMember
600nsec_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAggregateLossesI
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_CorporateDebtSecuritiesMember
12 Months or Longer, Fair Value 1,843us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_CorporateDebtSecuritiesMember
1,548us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_CorporateDebtSecuritiesMember
12 Months or Longer, Gross Unrealized Losses 41nsec_AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLossesI
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_CorporateDebtSecuritiesMember
113nsec_AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLossesI
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_CorporateDebtSecuritiesMember
Total Fair Value 8,149us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_CorporateDebtSecuritiesMember
12,137us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_CorporateDebtSecuritiesMember
Total Gross Unrealized Losses 405nsec_AvailableForSaleSecuritiesGrossUnrealizedLoss1
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_CorporateDebtSecuritiesMember
713nsec_AvailableForSaleSecuritiesGrossUnrealizedLoss1
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_CorporateDebtSecuritiesMember
Total Securities in a Loss Position 18us-gaap_AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositions1
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_CorporateDebtSecuritiesMember
26us-gaap_AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositions1
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_CorporateDebtSecuritiesMember
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Less than 12 Months, Fair Value 1,386us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
3,215us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Less than 12 Months, Gross Unrealized Losses 4nsec_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAggregateLossesI
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
427nsec_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAggregateLossesI
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
12 Months or Longer, Fair Value 1,855us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
1,796us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
12 Months or Longer, Gross Unrealized Losses 149nsec_AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLossesI
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
130nsec_AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLossesI
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Total Fair Value 3,241us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
5,011us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Total Gross Unrealized Losses 153nsec_AvailableForSaleSecuritiesGrossUnrealizedLoss1
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
557nsec_AvailableForSaleSecuritiesGrossUnrealizedLoss1
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Total Securities in a Loss Position 12us-gaap_AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositions1
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
18us-gaap_AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositions1
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Private Label Mortgage Backed Securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Less than 12 Months, Fair Value 0us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember
472us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember
Less than 12 Months, Gross Unrealized Losses 0nsec_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAggregateLossesI
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember
4nsec_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAggregateLossesI
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember
12 Months or Longer, Fair Value 97us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember
0us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember
12 Months or Longer, Gross Unrealized Losses 3nsec_AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLossesI
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember
0nsec_AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLossesI
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember
Total Fair Value 97us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember
472us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember
Total Gross Unrealized Losses 3nsec_AvailableForSaleSecuritiesGrossUnrealizedLoss1
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember
4nsec_AvailableForSaleSecuritiesGrossUnrealizedLoss1
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember
Total Securities in a Loss Position 1us-gaap_AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositions1
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember
3us-gaap_AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositions1
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_MortgageBackedSecuritiesIssuedByPrivateEnterprisesMember
US States and Political Subdivisions Debt Securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Less than 12 Months, Fair Value 0us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember
3,545us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember
Less than 12 Months, Gross Unrealized Losses 0nsec_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAggregateLossesI
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember
165nsec_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAggregateLossesI
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember
12 Months or Longer, Fair Value 651us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember
325us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember
12 Months or Longer, Gross Unrealized Losses 13nsec_AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLossesI
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember
30nsec_AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLossesI
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember
Total Fair Value 651us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember
3,870us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember
Total Gross Unrealized Losses 13nsec_AvailableForSaleSecuritiesGrossUnrealizedLoss1
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember
195nsec_AvailableForSaleSecuritiesGrossUnrealizedLoss1
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember
Total Securities in a Loss Position 2us-gaap_AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositions1
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember
11us-gaap_AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositions1
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USStatesAndPoliticalSubdivisionsMember
US Treasury Securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Less than 12 Months, Fair Value 1,475us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USTreasurySecuritiesMember
11,534us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USTreasurySecuritiesMember
Less than 12 Months, Gross Unrealized Losses 6nsec_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAggregateLossesI
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USTreasurySecuritiesMember
600nsec_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAggregateLossesI
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USTreasurySecuritiesMember
12 Months or Longer, Fair Value 3,499us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USTreasurySecuritiesMember
390us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USTreasurySecuritiesMember
12 Months or Longer, Gross Unrealized Losses 101nsec_AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLossesI
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USTreasurySecuritiesMember
108nsec_AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLossesI
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USTreasurySecuritiesMember
Total Fair Value 4,974us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USTreasurySecuritiesMember
11,924us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USTreasurySecuritiesMember
Total Gross Unrealized Losses 107nsec_AvailableForSaleSecuritiesGrossUnrealizedLoss1
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USTreasurySecuritiesMember
708nsec_AvailableForSaleSecuritiesGrossUnrealizedLoss1
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USTreasurySecuritiesMember
Total Securities in a Loss Position 10us-gaap_AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositions1
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USTreasurySecuritiesMember
21us-gaap_AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositions1
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_USTreasurySecuritiesMember
Equity Securities [Member]    
Schedule of Available-for-sale Securities [Line Items]    
Less than 12 Months, Fair Value 0us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_EquitySecuritiesMember
0us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_EquitySecuritiesMember
Less than 12 Months, Gross Unrealized Losses 0nsec_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAggregateLossesI
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_EquitySecuritiesMember
0nsec_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAggregateLossesI
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_EquitySecuritiesMember
12 Months or Longer, Fair Value 1,116us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_EquitySecuritiesMember
875us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_EquitySecuritiesMember
12 Months or Longer, Gross Unrealized Losses 170nsec_AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLossesI
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_EquitySecuritiesMember
411nsec_AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAggregateLossesI
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_EquitySecuritiesMember
Total Fair Value 1,116us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_EquitySecuritiesMember
875us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_EquitySecuritiesMember
Total Gross Unrealized Losses $ 170nsec_AvailableForSaleSecuritiesGrossUnrealizedLoss1
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_EquitySecuritiesMember
$ 411nsec_AvailableForSaleSecuritiesGrossUnrealizedLoss1
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_EquitySecuritiesMember
Total Securities in a Loss Position 1us-gaap_AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositions1
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_EquitySecuritiesMember
1us-gaap_AvailableforsaleSecuritiesInUnrealizedLossPositionsQualitativeDisclosureNumberOfPositions1
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_EquitySecuritiesMember