2.4.0.8161 - Disclosure - FAIR VALUE (Details Textual)truefalsefalse1false USDfalsefalse$P01_01_2013To06_30_2013http://www.sec.gov/CIK0001493552duration2013-01-01T00:00:002013-06-30T00:00:00USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$1true 3nvsl_FairValueLineItemsnvsl_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalselabel1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Fair Value [Line Items]2false 4us-gaap_PledgedAssetsSeparatelyReportedLoansPledgedAsCollateralAtFairValueus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalselabel1truefalsefalse87000008700000USD$falsetruefalsexbrli:monetaryItemTypemonetaryThe fair value, as of the date of each statement of financial position presented, of loans which are owned but transferred to serve as collateral for the payment of the related debt obligation primarily arising from secured borrowings and repurchase agreements, and that are reclassified and separately reported in the statement of financial position because the transferee has the right by contract or custom to sell or re-pledge them.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 30 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6467456&loc=d3e113888-111728 false2Pledged Assets Separately Reported, Loans Pledged as Collateral, at Fair Value, Total3false 4nvsl_FairValueOfForeclosedRealEstatenvsl_falsedebitdurationfalsefalsefalsefalsefalsefalsefalsefalselabel1truefalsefalse153000153000falsefalsefalsexbrli:monetaryItemTypemonetaryThe estimated fair value of foreclosed real estate during the period.No definition available.false2Fair Value Of Foreclosed Real Estate4false 4us-gaap_AmortizationOfMortgageServicingRightsMSRsus-gaap_truedebitdurationfalsefalsefalsefalsefalsefalsefalsefalselabel1truefalsefalse16000001600000USD$falsetruefalsexbrli:monetaryItemTypemonetaryThe periodic amortization (in proportion to and over the period of estimated net servicing income or loss) of capitalized servicing rights, which contractually entitle the servicer to receive fees and ancillary revenues for performing billing, collection, disbursement and recordkeeping services in connection with a mortgage portfolio. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 50 -Section 50 -Paragraph 4 -Subparagraph (a)(4) -URI http://asc.fasb.org/extlink&oid=7882072&loc=d3e122739-111746 false2Amortization Of Mortgage Servicing Rights (Msrs)falseFAIR VALUE (Details Textual) (USD $)NoRoundingUnKnownUnKnownUnKnowntruefalsefalseSheethttp://www.nvsl.com/role/FairValueDetailsTextual14