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           Summary of Significant Accounting Policies 
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        12 Months Ended | |
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           Dec. 31, 2013 
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| Organization, Consolidation and Presentation of Financial Statements [Abstract] | ||
| Significant Accounting Policies [Text Block] |                NOTE 1 - Summary of Significant Accounting  Policies
         Principles of Consolidation  The consolidated  financial statements include NorthWest Indiana Bancorp (the  “Bancorp”), its wholly owned subsidiary, Peoples Bank  SB (the “Bank”), and the Bank’s wholly owned  subsidiaries, Peoples Service Corporation, NWIN, LLC, and NWIN  Funding, Incorporated, and Columbia Development Company, LLC. The  Bancorp has no other business activity other than being a holding  company for the Bank. The Bancorp’s earnings are dependent  upon the earnings of the Bank. Peoples Service Corporation provides  insurance and annuity investments to the Bank’s wealth  management customers. NWIN, LLC is located in Las Vegas, Nevada and  serves as the Bank’s investment subsidiary and parent of a  real estate investment trust, NWIN Funding, Inc. NWIN Funding, Inc.  was formed as an Indiana Real Estate Investment Trust. The  formation of NWIN Funding, Inc. provides the Bancorp with a vehicle  that may be used to raise capital utilizing portfolio mortgages as  collateral, without diluting stock ownership. In addition, NWIN  Funding, Inc. will receive favorable state tax treatment for income  generated by its operations. Columbia Development Company is a  limited liability company that serves to hold certain real estate  properties that are acquired through foreclosure. All significant  inter-company accounts and transactions have been eliminated in  consolidation.              Use of Estimates  Preparing financial statements  in conformity with accounting principles generally accepted in the  United States of America requires management to make estimates and  assumptions that affect the reported amounts of assets, liabilities  and disclosure of contingent assets and liabilities at the date of  the financial statements and the reported amounts of revenue and  expenses during the reporting period, as well as the disclosures  provided. Actual results could differ from those estimates.  Estimates associated with the allowance for loan losses, mortgage  servicing rights, fair values of foreclosed real estate, financial  instruments and investment securities, and the status of  contingencies are particularly susceptible to material change in  the near term.              Concentrations of Credit Risk  The Bancorp grants  residential, commercial real estate, commercial business and  installment loans to customers primarily in Lake County, in  northwest Indiana. The Bancorp is also an active lender in Porter  County, and to a lesser extent, LaPorte, Newton, and Jasper  counties in Indiana, and Lake, Cook and Will counties in Illinois.  Substantially all loans are secured by specific items of collateral  including residences, commercial real estate, business assets, and  consumer assets.              Cash Flow Reporting  For purposes of the  statements of cash flows, the Bancorp considers cash on hand,  noninterest bearing deposits in other financial institutions, all  interest-bearing deposits in other financial institutions with  original maturities of 90 days or less, and federal funds sold to  be cash and cash equivalents. The Bancorp reports net cash flows  for customer loan and deposit transactions and short-term  borrowings with maturities of 90 days or less.              Securities  The Bancorp classifies securities into  held-to-maturity, available-for-sale, or trading categories.  Held-to-maturity securities are those which management has the  positive intent and the Bancorp has the ability to hold to  maturity, and are reported at amortized cost. Available-for-sale  securities are those the Bancorp may decide to sell if needed for  liquidity, asset-liability management or other reasons.  Available-for-sale securities are reported at fair value, with  unrealized gains and losses reported in other comprehensive income,  net of tax. The Bancorp does not have a trading portfolio. Realized  gains and losses resulting from the sale of securities recorded on  the trade date are computed by the specific identification method.  Interest and dividend income, adjusted by amortization of premiums  or discounts on a level yield method, are included in earnings.  Securities are reviewed for other-than-temporary impairment on a  quarterly basis.       The Bancorp considers the following factors when determining an  other-than-temporary impairment for a security: the length of time  and the extent to which the market value has been less than  amortized cost; the financial condition and near-term prospects of  the issuer; the underlying fundamentals of the relevant market and  the outlook for such market for the near future; and an assessment  of whether the Bancorp has (1) the intent to sell the debt security  or (2) it is more likely than not that the Bancorp will be required  to sell the debt security before its anticipated market recovery.  If either of these conditions are met, management will recognize  other-than-temporary impairment. If, in management’s  judgment, an other-than-temporary impairment exists, the cost basis  of the security will be written down for the credit loss, and the  unrealized credit loss will be transferred from accumulated other  comprehensive loss as an immediate reduction of current  earnings.              Loans Held-for-Sale  Mortgage loans originated and  intended for sale in the secondary market are carried at the lower  of aggregate cost or fair market value, as determined by  outstanding commitments from investors. Net unrealized losses, if  any, are recorded as a valuation allowance and charged to  earnings.       Mortgage loans held-for-sale can be sold with servicing rights  retained or released. The carrying value of mortgage loans sold is  reduced by the amount allocated to the servicing rights. Gains and  losses on sales of mortgage loans are based on the difference  between the selling price and the carrying value of the related  loan sold.              Loans and Loan Income  Loans that management has  the intent and ability to hold for the foreseeable future or until  maturity or payoff are reported at the principal balance  outstanding, net of unearned interest, net deferred loan fees and  costs, and an allowance for loan losses. Interest income is accrued  on the unpaid principal balance. Loan origination fees, net of  certain direct origination costs, are deferred and recognized in  interest income using the level-yield method without anticipating  prepayments.       The accrual of interest income on mortgage and commercial loans is  discontinued at the time the loan is 90 days delinquent unless the  loan is well-secured and in process of collection. Consumer loans  are typically charged-off no later than when they reach 120 days  past due. Past due status is based on the contractual terms of the  loan. In all cases, loans are placed on non-accrual or charged-off  status at an earlier date if collection of principal or interest is  considered doubtful.       Generally, interest accrued but not received for loans placed on  non-accrual status is reversed against interest income. Interest  received on such loans is accounted for on the cash-basis or  cost-recovery method, until qualifying for return to accrual. Loans  are returned to accrual status when all the principal and interest  amounts contractually due are brought current and future payments  are reasonably assured.              Allowance for Loan Losses  The allowance for loan  losses (allowance) is a valuation allowance for probable incurred  credit losses. Loan losses are charged against the allowance when  management believes the uncollectibility of a loan balance is  confirmed. Subsequent recoveries, if any, are credited to the  allowance. Management estimates the allowance balance required  using past loan loss experience, the nature and volume of the  portfolio, information about specific borrower situations and  estimated collateral values, economic conditions, and other  factors. Allocations of the allowance may be made for specific  loans, but the entire allowance is available for any loan that, in  management’s judgment, should be charged-off.       A loan is considered impaired when, based on current information  and events, it is probable that the Bancorp will be unable to  collect the scheduled payments of principal or interest when due  according to the contractual terms of the loan agreement. Factors  considered by management in determining impairment include payment  status, collateral value, and the probability of collecting  scheduled principal and interest payments when due. Loans that  experience insignificant payment delays and payment shortfalls  generally are not classified as impaired. Management determines the  significance of payment delays and payment shortfalls on a case by  case basis, taking into consideration all of the circumstances  surrounding the loan and the borrower, including the length of the  delay, the reasons for the delay, the borrower’s prior  payment record, and the amount of the shortfall in relation to the  principal and interest owed. Impairment is measured on a loan by  loan basis for commercial and construction loans by either the  present value of expected future cash flows discounted at the  loan’s effective interest rate, the loan’s obtainable  market price, or the fair value of the collateral if the loan is  collateral dependent. Large groups of smaller balance homogeneous  loans are collectively evaluated for impairment. Accordingly, the  Bancorp does not separately identify individual consumer and  residential loans for impairment disclosures.          
  Federal Home Loan Bank Stock  The Bank is a member  of the FHLB system. Members are required to own a certain amount of  stock based on the level of borrowings and other factors, and may  invest in additional amounts. FHLB stock is carried at cost,  classified as a restricted security, and periodically evaluated for  impairment based on ultimate recovery of par value. Both cash and  stock dividends are reported as income.          
  Transfers of Financial Assets  Transfers of  financial assets are accounted for as sales when control over the  assets has been surrendered. Control over transferred assets is  deemed to be surrendered when (1) the assets have been isolated  from the Bancorp, (2) the transferee obtains the right (free of  conditions that constrain it from taking advantage of the right) to  pledge or exchange the transferred assets, and (3) the Bancorp does  not maintain effective control over the transferred assets through  an agreement to repurchase them before their maturity.          
  Premises and Equipment  Land is carried at cost.  Premises and equipment are carried at cost less accumulated  depreciation. Premises and related components are depreciated using  the straight-line method with useful lives ranging from   26 to 39  years. Furniture and equipment are depreciated using the  straight-line method with useful lives ranging from 2  to 10  years.          
  Foreclosed Real Estate  Assets acquired through or  instead of loan foreclosure are initially recorded at fair value  less estimated costs to sell when acquired, establishing a new cost  basis. If fair value declines subsequent to foreclosure, a  valuation allowance is recorded through expense. Operating costs  after acquisition are expensed.          
  Long-term Assets  Premises and equipment and other  long-term assets are reviewed for impairment when events indicate  their carrying amount may not be recoverable from future  undiscounted cash flows. If impaired, the assets are recorded at  fair value.          
  Bank Owned Life Insurance  The Bancorp has  purchased life insurance policies on certain key executives. In  accordance with accounting for split-dollar life insurance, Bank  owned life insurance is recorded at the amount that can be realized  under the insurance contract at the balance sheet date, which is  the cash surrender value adjusted for other charges or other  amounts due that are probable at settlement.          
  Repurchase Agreements  Substantially, all  repurchase agreement liabilities represent amounts advanced by  various customers that are not covered by federal deposit insurance  and are secured by securities owned by the Bancorp.          
  Postretirement Benefits Other Than Pensions  The  Bancorp sponsors a defined benefit postretirement plan that  provides comprehensive major medical benefits to all eligible  retirees. Postretirement benefits are accrued based on the expected  cost of providing postretirement benefits to employees during the  years the employees have rendered service to the Bancorp.          
  Income Taxes  Income tax expense is the total of  the current year income tax due or refundable and the change in  deferred tax assets and liabilities. Deferred tax assets and  liabilities are the expected future tax amounts for the temporary  differences between carrying amounts and tax bases of assets and  liabilities, computed using enacted tax rates. A valuation  allowance, if needed, reduces deferred tax assets to the amount  expected to be realized.          
  Loan Commitments and Related Financial Instruments   Financial instruments include off-balance sheet credit  instruments, such as commitments to make loans and standby letters  of credit, issued to meet customer financing needs. The face amount  for these items represents the exposure to loss, before considering  customer collateral or ability to repay. Such financial instruments  are recorded when they are funded.          
  Earnings Per Common Share  Basic earnings per  common share is net income divided by the weighted-average number  of common shares outstanding during the period. Diluted earnings  per common share includes the dilutive effect of additional  potential common shares issuable under stock options.          
  Comprehensive Income  Comprehensive income  consists of net income and other comprehensive income. Other  comprehensive income includes unrealized gains and losses on  securities available-for-sale and the unrecognized gains and losses  on postretirement benefits.          
  Loss Contingencies  Loss contingencies, including  claims and legal actions arising in the ordinary course of  business, are recorded as liabilities when the likelihood of loss  is probable and an amount or range of loss can be reasonably  estimated. Management does not believe such matters currently exist  that will have a material effect on the financial statements.              Restrictions on Cash  Cash on hand or on deposit  with the Federal Reserve Bank of $656,000  and $572,000  was required to meet regulatory reserve and clearing requirements  at December 31, 2013 and 2012, respectively. These balances do not  earn interest.          
  Fair Value of Financial Instruments  Fair values  of financial instruments are estimated using relevant market  information and other assumptions, as more fully disclosed in a  separate note. Fair value estimates involve uncertainties and  matters of significant judgment regarding interest rates, credit  risk, prepayments and other factors, especially in the absence of  broad markets for particular instruments. Changes in assumptions or  in market conditions could significantly affect the  estimates.          
  Operating Segments  While the Bancorp's executive  management monitors the revenue streams of the various products and  services, the identifiable segments are not material and operations  are managed and financial performance is evaluated on a  company-wide basis. Accordingly, all of the Bancorp's financial  service operations are considered by management to be aggregated in  one reportable operating segment.          
  Reclassification  Certain amounts appearing in the  consolidated financial statements and notes thereto for the year  ended December 31, 2012, may have been reclassified to conform to  the December 31, 2013 presentation.              Acquisition Activity  On December 20, 2013, the  Bank signed a definitive agreement to acquire First Federal Savings  and Loan Association of Hammond (the “Association”), a  federal mutual savings association headquartered in Hammond,  Indiana. The Bank will acquire the Association by merging the  Association with and into the Bank immediately following the  Association’s voluntary supervisory conversion from mutual to  stock form. Neither the Bancorp nor the Bank will issue or pay any  shares, cash, or other consideration in the merger. The  Bank’s acquisition of the Association is subject to customary  closing conditions, including regulatory approvals by the OCC,  FDIC, and DFI. No approval of the members of the Association is  required for the transaction. The Bank and the Association make  certain customary representations and warranties in the definitive  acquisition agreement, which will terminate at the closing. The  Association has a home office and branch office in Lake County,  Indiana, and is expected to add approximately $40.7 million in  assets to the Bank, based on the Association’s September 30,  2013 financial statements. The merger is expected to close in the  second quarter of 2014.       Adoption of New Accounting Pronouncements
       Update Number 2013-02  Comprehensive Income (Topic 220):  Reporting of Amounts Reclassified Out of Accumulated Other  Comprehensive Income. The amendments in this Update supersede  and replace the presentation requirements for reclassifications out  of accumulated other comprehensive income in ASUs 2011-05 (issued  in June 2011) and 2011-12 (issued in December 2011) for all public  and private organizations. The amendments require an entity to  provide additional information about reclassifications out of  accumulated other comprehensive income. For public entities, the  amendments are effective prospectively for reporting periods  beginning after December 15, 2012. The amendments did not change  the Bancorp’s presentation of the Consolidated Statements of  Comprehensive Income.
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