Significant Accounting Policies (Policies)	6 Months Ended
Significant Accounting Policies (Policies)	Jun. 30, 2019
Accounting Policies [Abstract]
Overview	The accompanying Consolidated Financial Statements include the accounts of Unity Bancorp, Inc. (the "Parent Company") and its wholly-owned subsidiary, Unity Bank (the "Bank" or when consolidated with the Parent Company, the "Company"), and reflect all adjustments and disclosures which are generally routine and recurring in nature, and in the opinion of management, necessary for a fair presentation of interim results. The Bank has multiple subsidiaries used to hold part of its investment and loan portfolios and OREO properties. All significant intercompany balances and transactions have been eliminated in consolidation. Certain reclassifications have been made to prior period amounts to conform to the current year presentation, with no impact on current earnings or shareholders’ equity. The financial information has been prepared in accordance with U.S. generally accepted accounting principles and has not been audited. In preparing the financial statements, management is required to make estimates and assumptions that affect the reported amounts of assets and liabilities and revenues and expenses during the reporting periods. Actual results could differ from those estimates. Amounts requiring the use of significant estimates include the allowance for loan losses, valuation of deferred tax and servicing assets, the carrying value of loans held for sale and other real estate owned, the valuation of securities and the determination of other-than-temporary impairment for securities and fair value disclosures. Management believes that the allowance for loan losses is adequate. While management uses available information to recognize losses on loans, future additions to the allowance for loan losses may be necessary based on changes in economic conditions. The Company has evaluated subsequent events for potential recognition and/or disclosure through the date the Consolidated Financial Statements included in this Quarterly Report on Form 10-Q were available to be issued. The interim unaudited Consolidated Financial Statements included herein have been prepared in accordance with instructions for Form 10-Q and the rules and regulations of the Securities and Exchange Commission (“SEC”) and consist of normal recurring adjustments necessary for the fair presentation of interim results. The results of operations for the three and six months ended June 30, 2019 are not necessarily indicative of the results which may be expected for the entire year. As used in this Form 10-Q, “we” and “us” and “our” refer to Unity Bancorp, Inc., and its consolidated subsidiary, Unity Bank, depending on the context. Certain information and financial disclosures required by U.S. generally accepted accounting principles have been condensed or omitted from interim reporting pursuant to SEC rules. Interim financial statements should be read in conjunction with the Company’s Consolidated Financial Statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2018.
Other-Than-Temporary Impairment	Other-Than-Temporary Impairment The Company has a process in place to identify securities that could potentially incur credit impairment that is other-than-temporary. This process involves monitoring late payments, pricing levels, downgrades by rating agencies, key financial ratios, financial statements, revenue forecasts and cash flow projections as indicators of credit issues. Management evaluates securities for other-than-temporary impairment at least on a quarterly basis, and more frequently when economic or market concern warrants such evaluation. This evaluation considers relevant facts and circumstances in evaluating whether a credit or interest rate-related impairment of a security is other-than-temporary. Relevant facts and circumstances considered include: (1) the extent and length of time the fair value has been below cost; (2) the reasons for the decline in value; (3) the financial position and access to capital of the issuer, including the current and future impact of any specific events and (4) for fixed maturity securities, our intent to sell a security or whether it is more likely than not we will be required to sell the security before the recovery of its amortized cost which, in some cases, may extend to maturity and for equity securities, our ability and intent to hold the security for a forecasted period of time that allows for the recovery in value. Management assesses its intent to sell or whether it is more likely than not that it will be required to sell a security before recovery of its amortized cost basis less any current-period credit losses. For debt securities that are considered other-than-temporarily impaired with no intent to sell and no requirement to sell prior to recovery of its amortized cost basis, the amount of the impairment is separated into the amount that is credit related (credit loss component) and the amount due to all other factors. The credit loss component is recognized in earnings and is the difference between the security’s amortized cost basis and the present value of its expected future cash flows. The remaining difference between the security’s fair value and the present value of future expected cash flows is due to factors that are not credit related and is recognized in other comprehensive income. For debt securities where management has the intent to sell, the amount of the impairment is reflected in earnings as realized losses. The present value of expected future cash flows is determined using the best estimate cash flows discounted at the effective interest rate implicit to the security at the date of purchase or the current yield to accrete an asset-backed or floating rate security. The methodology and assumptions for establishing the best estimate cash flows vary depending on the type of security. The asset-backed securities cash flow estimates are based on bond specific facts and circumstances that may include collateral characteristics, expectations of delinquency and default rates, loss severity and prepayment speeds and structural support, including subordination and guarantees. The corporate bond cash flow estimates are derived from scenario-based outcomes of expected corporate restructurings or the disposition of assets using bond specific facts and circumstances including timing, security interests and loss severity.
Transfers of Financial Assets	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 Company, (2) the transferee obtains the right (free of conditions that constrain it from taking advantage of that right) to pledge or exchange the transferred assets, and (3) the Company does not maintain effective control over the transferred assets through an agreement to repurchase them before their maturity.
Loans	Loans Loans Held for Sale Loans held for sale represent the guaranteed portion of Small Business Administration (“SBA”) loans and are reflected at the lower of aggregate cost or market value. The Company originates loans to customers under an SBA program that historically has provided for SBA guarantees of up to 90 percent of each loan. The Company generally sells the guaranteed portion of its SBA loans to a third party and retains the servicing, holding the nonguaranteed portion in its portfolio. The net amount of loan origination fees on loans sold is included in the carrying value and in the gain or loss on the sale. When sales of SBA loans do occur, the premium received on the sale and the present value of future cash flows of the servicing assets are recognized in income. All criteria for sale accounting must be met in order for the loan sales to occur; see details under the “Transfers of Financial Assets” heading above. Servicing assets represent the estimated fair value of retained servicing rights, net of servicing costs, at the time loans are sold. Servicing assets are amortized in proportion to, and over the period of, estimated net servicing revenues. Impairment is evaluated based on stratifying the underlying financial assets by date of origination and term. Fair value is determined using prices for similar assets with similar characteristics, when available, or based upon discounted cash flows using market-based assumptions. Any impairment, if temporary, would be reported as a valuation allowance. Serviced loans sold to others are not included in the accompanying Consolidated Balance Sheets. Income and fees collected for loan servicing are credited to noninterest income when earned, net of amortization on the related servicing assets. Loans Held to Maturity Loans held to maturity are stated at the unpaid principal balance, net of unearned discounts and deferred loan origination fees and costs. In accordance with the level yield method, loan origination fees, net of direct loan origination costs, are deferred and recognized over the estimated life of the related loans as an adjustment to the loan yield. Interest is credited to operations primarily based upon the principal balance outstanding. Loans are reported as past due when either interest or principal is unpaid in the following circumstances: fixed payment loans when the borrower is in arrears for two or more monthly payments; open end credit for two or more billing cycles; and single payment notes if interest or principal remains unpaid for 30 days or more. Nonperforming loans consist of loans that are not accruing interest as a result of principal or interest being in default for a period of 90 days or more or when the ability to collect principal and interest according to the contractual terms is in doubt (nonaccrual loans). When a loan is classified as nonaccrual, interest accruals are discontinued and all past due interest previously recognized as income is reversed and charged against current period earnings. Generally, until the loan becomes current, any payments received from the borrower are applied to outstanding principal until such time as management determines that the financial condition of the borrower and other factors merit recognition of a portion of such payments as interest income. Loans may be returned to an accrual status when the ability to collect is reasonably assured and when the loan is brought current as to principal and interest. Loans are charged off when collection is sufficiently questionable and when the Company can no longer justify maintaining the loan as an asset on the balance sheet. Loans qualify for charge-off when, after thorough analysis, all possible sources of repayment are insufficient. These include: 1) potential future cash flows, 2) value of collateral, and/or 3) strength of co-makers and guarantors. All unsecured loans are charged off upon the establishment of the loan’s nonaccrual status. Additionally, all loans classified as a loss or that portion of the loan classified as a loss is charged off. All loan charge-offs are approved by the Board of Directors. Troubled debt restructurings ("TDRs") occur when a creditor, for economic or legal reasons related to a debtor’s financial condition, grants a concession to the debtor that it would not otherwise consider. These concessions typically include reductions in interest rate, extending the maturity of a loan, or a combination of both. Interest income on accruing TDRs is credited to operations primarily based upon the principal amount outstanding, as stated in the paragraphs above. The Company evaluates its loans for impairment. A loan is considered impaired when, based on current information and events, it is probable that the Company will be unable to collect all amounts due according to the contractual terms of the loan agreement. The Company has defined impaired loans to be all TDRs and nonperforming loans individually evaluated for impairment. Impairment is evaluated in total for smaller-balance loans of a similar nature (consumer and residential mortgage loans), and on an individual basis for all other loans. Impairment of a loan is measured based on the present value of expected future cash flows, discounted at the loan's effective interest rate, or as a practical expedient, based on a loan’s observable market price or the fair value of collateral, net of estimated costs to sell, if the loan is collateral-dependent. If the value of the impaired loan is less than the recorded investment in the loan, the Company establishes a valuation allowance, or adjusts existing valuation allowances, with a corresponding charge to the provision for loan losses.
Allowance for Loan Losses and Reserve for Unfunded Loan Commitments	Allowance for Loan Losses and Reserve for Unfunded Loan Commitments The allowance for loan losses is maintained at a level management considers adequate to provide for probable loan losses as of the balance sheet date. The allowance is increased by provisions charged to expense and is reduced by net charge-offs. The level of the allowance is based on management’s evaluation of probable losses in the loan portfolio, after consideration of prevailing economic conditions in the Company’s market area, the volume and composition of the loan portfolio, and historical loan loss experience. The allowance for loan losses consists of specific reserves for individually impaired credits and TDRs, reserves for nonimpaired loans based on historical loss factors and reserves based on general economic factors and other qualitative risk factors such as changes in delinquency trends, industry concentrations or local/national economic trends. This risk assessment process is performed at least quarterly, and, as adjustments become necessary, they are realized in the periods in which they become known. Although management attempts to maintain the allowance at a level deemed adequate to provide for probable losses, future additions to the allowance may be necessary based upon certain factors including changes in market conditions and underlying collateral values. In addition, various regulatory agencies periodically review the adequacy of the Company’s allowance for loan losses. These agencies may require the Company to make additional provisions based on their judgments about information available to them at the time of their examination. The Company maintains an allowance for unfunded loan commitments that is maintained at a level that management believes is adequate to absorb estimated probable losses. Adjustments to the allowance are made through other expenses and applied to the allowance which is maintained in other liabilities.
Income Taxes	Income Taxes The Company accounts for income taxes according to the asset and liability method. Under this method, deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax basis. Deferred tax assets and liabilities are measured using the enacted tax rates applicable to taxable income for the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. Valuation reserves are established against certain deferred tax assets when it is more likely than not that the deferred tax assets will not be realized. Increases or decreases in the valuation reserve are charged or credited to the income tax provision. When tax returns are filed, it is highly certain that some positions taken would be sustained upon examination by the taxing authorities, while others are subject to uncertainty about the merits of the position taken or the amount of the position that ultimately would be sustained. The benefit of a tax position is recognized in the financial statements in the period during which, based on all available evidence, management believes it is more likely than not that the position will be sustained upon examination, including the resolution of appeals or litigation processes, if any. The evaluation of a tax position taken is considered by itself and not offset or aggregated with other positions. Tax positions that meet the more likely than not recognition threshold are measured as the largest amount of tax benefit that is more than 50 percent likely of being realized upon settlement with the applicable taxing authority. The portion of benefits associated with tax positions taken that exceeds the amount measured as described above is reflected as a liability for unrecognized tax benefits in the accompanying balance sheet along with any associated interest and penalties that would be payable to the taxing authorities upon examination. Interest and penalties associated with unrecognized tax benefits would be recognized in income tax expense on the income statement.
New Accounting Pronouncements	New Accounting Pronouncements ASU 2016-13, "Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments." ASU 2016-13 was issued to replace the incurred loss impairment methodology in current GAAP with an expected credit loss methodology and requires consideration of a broader range of information to determine credit loss estimates. Financial assets measured at amortized cost will be presented at the net amount expected to be collected by using an allowance for credit losses. Purchased credit impaired loans will receive an allowance account at the acquisition date that represents a component of the purchase price allocation. Credit losses relating to available-for-sale debt securities will be recorded through an allowance for credit losses, with such allowance limited to the amount by which fair value is below amortized cost. For public business entities, ASU 2016-13 is effective for interim and annual reporting periods beginning after December 15, 2019. In May 2019, FASB issued ASU 2019-05, "Financial Instruments - Credit Losses (Topic 326): Targeted Transition Relief." ASU 2019-05 was issued to address concerns with the adoption of ASU 2016-13. ASU 2019-05 gives entities the ability to irrevocable elect the fair value option in Subtopic 825-10 for certain existing financial assets upon transition to ASU 2016-03. Financial assets that are eligible for this fair value election are those that qualify under Subtopic 825-10 and are within the scope of Subtopic 326-10, "Financial Instruments - Credit Losses - Measured at Amortized Costs." An exception to this is held-to-maturity debt securities, which do not qualify for this transition election. The effective date for the amendment is the same as the effective date in ASU 2016-03. The Company is currently evaluating the impact of the adoption of ASU 2016-13 on its consolidated financial statements. ASU 2017-04, "Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment." ASU 2017-04 was issued in an effort to simplify accounting in a new standard. The amendments in this update require that an entity perform its annual or interim goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. The amendment states that an entity should recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit's fair value, but the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. For public business entities, ASU 2017-04 is effective for fiscal years beginning after December 15, 2019. Early adoption is permitted for interim or annual goodwill impairment tests performing on testing dates after January 1, 2017. The Company does not expect this ASU to have a material impact on the Company's consolidated financial statements since the fair values of our reporting units were not lower than their respective carrying amounts at the time of our goodwill impairment analysis for 2018.
Benefit Plans	Benefit Plans In addition to the 401(k) savings plan which covers substantially all employees, in 2015 the Company established an unfunded supplemental defined benefit plan to provide additional retirement benefits for the President and Chief Executive Officer (“CEO”) and certain key executives. On June 4, 2015, the Company approved the Supplemental Executive Retirement Plan (“SERP”) pursuant to which the President and CEO is entitled to receive certain supplemental nonqualified retirement benefits. On September 27, 2018 the Company approved a change in calculation of the Retirement Benefit payable under the Plan so that the Retirement Benefit shall be an amount equal to sixty percent (60%) of the average of Executive's base salary for the thirty-six (36) months immediately preceding executive's separation from service after age 66, adjusted annually thereafter by two percent (2%). The total benefit is to be made payable in fifteen annual installments. The future payments are estimated to total $6.6 million. A discount rate of four percent (4%) was used to calculate the present value of the benefit obligation. The President and CEO commenced vesting in this retirement benefit on January 1, 2014, and vests an additional three percent (3%) each year until fully vested on January 1, 2024. In the event that the President and CEO’s separation from service from the company were to occur prior to full vesting, the President and CEO would be entitled to and shall be paid the vested portion of the retirement benefit calculated as of the date of separation from service. Notwithstanding the foregoing, upon a Change in Control, and provided that within 6 months following the Change in Control the President and CEO is involuntarily terminated for reasons other than “cause” or the President and CEO resigns for “good reason”, as such is defined in the SERP, or the President and CEO voluntarily terminates his employment after being offered continued employment in a position that is not a “Comparable Position”, as such is also defined in the SERP, the President and CEO shall become one hundred percent (100%) vested in the full retirement benefit.

Disclosure of accounting policy for those finance, loan and lease receivables classified as held for investment. This disclosure may include (1) the basis at which such receivables are carried in the entity's statements of financial position (2) how the level of the allowance for loan and lease losses is determined (3) when impairments, charge-offs or recoveries are recognized for such receivables (4) the treatment of commitment and other fees and loan origination costs (including, if applicable, how the entity accounts for fees and costs associated with credit cards that are either purchased or originated) (5) the treatment of any premiums or discounts or unearned income (6) the entity's income recognition policies for such receivables, including those that are impaired, past due or placed on nonaccrual status (for impaired loans, the policy for recognizing interest income on such loans, including how cash receipts are recorded) and (7) the treatment of foreclosures or repossessions.

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Disclosure of accounting policy for income taxes, which may include its accounting policies for recognizing and measuring deferred tax assets and liabilities and related valuation allowances, recognizing investment tax credits, operating loss carryforwards, tax credit carryforwards, and other carryforwards, methodologies for determining its effective income tax rate and the characterization of interest and penalties in the financial statements.

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- Definition

Disclosure of accounting policy for pension and other postretirement benefit plans. This accounting policy may address (1) the types of plans sponsored by the entity, and the benefits provided by each plan (2) groups that participate in (or are covered by) each plan (3) how plan assets, liabilities and expenses are measured, including the use of any actuaries and (4) significant assumptions used by the entity to value plan assets and liabilities and how such assumptions are derived.

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