Summary of Significant Accounting Policies (Policies)	12 Months Ended
Summary of Significant Accounting Policies (Policies)	Dec. 31, 2019
Accounting Policies [Abstract]
Segment reporting	In addition, the consolidated financial statements include corporate and eliminations, which is comprised of enterprise-wide functional departments.
Basis of consolidation	Basis of consolidation The consolidated financial statements include the accounts of PAR Technology Corporation and its consolidated subsidiaries (ParTech, Inc., ParTech (Shanghai) Company Ltd., PAR Springer-Miller Systems, Inc., Springer-Miller Canada, ULC, PAR Canada ULC, Brink Software, Inc., AccSys, LLC, PAR Government Systems Corporation and Rome Research Corporation), collectively referred to as the “Company.” All significant intercompany transactions have been eliminated in consolidation.
Business combinations	Business combinations The Company accounts for business combinations pursuant to ASC 805, Business Combinations, which requires that assets acquired and liabilities assumed be recorded at their respective fair values on the date of acquisition. The fair value of the consideration paid is assigned to the underlying net assets of the acquired business based on their respective fair values. Any excess of the purchase price over the estimated fair values of the net assets acquired is allocated to goodwill (the “Acquisition Method”). The purchase price allocation process requires the Company to make significant assumptions and estimates in determining the purchase price and the assets acquired and liabilities assumed at the acquisition date. The Company’s assumptions and estimates are subject to refinement and, as a result, during the measurement period, which may be up to one year from the acquisition date, the Company records adjustments to the assets acquired and liabilities assumed with the corresponding offset to goodwill. Upon conclusion of the measurement period, any subsequent adjustments are recorded to the Company’s consolidated statements of operations. The Company’s consolidated financial statements and results of operations reflect an acquired business after the completion of the acquisition.
Contingent consideration	Contingent consideration The Company determines the acquisition date fair value of contingent consideration using a discounted cash flow method, with significant inputs that are not observable in the market and thus represents a Level 3 fair value measurement as defined in ASC 820, Fair Value Measurement. As it relates to the contingent consideration associated with the Brink Acquisition and the Restaurant Magic Acquisition we may use various valuation techniques depending on the terms and conditions of the contingent consideration, including a Monte-Carlo simulation. This simulation uses probability distribution for each significant input to produce hundreds or thousands of possible outcomes and the results are analyzed to determine probabilities of different outcomes occurring. Significant increases or decreases to these inputs in isolation would result in a significantly higher or lower liability with a higher liability capped by the contractual maximum of the contingent earn-out obligation. Ultimately, the liability will be equivalent to the amount paid, and the difference between the fair value estimate and amount paid will be recorded in earnings. The amount paid that is less than or equal to the liability on the acquisition date is reflected as cash used in financing activities in our consolidated statements of cash flows. Any amount paid in excess of the liability on the acquisition date is reflected as cash used in operating activities. The Restaurant Magic Acquisition resulted in a liability for the contingent consideration being recorded in the amount of $3.3 million during 2019. The liability for the contingent consideration was established at the time of the acquisition and will be evaluated quarterly based on additional information as it becomes available. Any change in the fair value adjustment is recorded in the earnings of that period.
Warranty provisions	Warranty provisions Warranty provisions for product warranties are recorded in the period in which the Company becomes obligated to honor the warranty, which generally is the period in which the related product revenue is recognized. The Company accrues warranty reserves based upon historical factors such as labor rates, average repair time, travel time, number of service calls per machine and cost of replacement parts. When a sale is consummated, a warranty reserve is recorded based upon the estimated cost to provide the service over the warranty period which can range from 12 months to 36 months.
Cash and cash equivalents	Cash and cash equivalents The Company considers all highly liquid investments, purchased with a remaining maturity of three months or less, to be cash equivalents.
Accounts receivable - Allowance for doubtful accounts	Accounts receivable – Allowance for doubtful accounts Allowances for doubtful accounts are based on estimates of probable losses related to accounts receivable balances. The establishment of allowances requires the use of judgment and assumptions regarding probable losses on receivable balances. The Company continuously monitors collections and payments from our customers and maintains a provision for estimated credit losses based on our historical experience and any specific customer collection issues that we have identified. Thus, if the financial condition of our customers were to deteriorate, our actual losses may exceed our estimates, and additional allowances would be required.
Inventories	Inventories The Company’s inventories are valued at the lower of cost and net realizable value, with cost determined using the first-in, first-out (“FIFO”) method. The Company uses certain estimates and judgments and considers several factors including product demand, changes in customer requirements and changes in technology to provide for excess and obsolescence reserves to properly value inventory.
Property, plant and equipment	Property, plant and equipment Property, plant and equipment are recorded at cost and depreciated using the straight-line method over the estimated useful lives of the assets, which range from three to twenty-five years. Expenditures for maintenance and repairs are expensed as incurred.
Other assets	Other assets Other assets primarily consist of cash surrender value of life insurance related to the Company’s Deferred Compensation Plan eligible to certain employees. The funded balance is reviewed on an annual basis.
Income taxes	Income taxes The provision for income taxes is based upon pretax earnings with deferred income taxes provided for the temporary differences between the financial reporting basis and the tax basis of the Company’s assets and liabilities. The Company records a valuation allowance when necessary to reduce deferred tax assets to their net realizable amounts. 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.
Other current liabilities	Other current liabilities Other current liabilities represent the fair value of the contingent consideration payable related to the Brink Acquisition.
Other long-term liabilities	Other long-term liabilities Other long-term liabilities represent amounts owed to employees that participate in the Company’s Deferred Compensation Plan and contingent consideration payable related to the Restaurant Magic Acquisition.
Foreign currency	Foreign currency The assets and liabilities for the Company’s international operations are translated into U.S. dollars using year-end exchange rates. Income statement items are translated at average exchange rates prevailing during the year. The resulting translation adjustments are recorded as a separate component of shareholders’ equity under the heading Accumulated Other Comprehensive Loss. Exchange gains and losses on intercompany balances of permanently invested long-term loans are also recorded as a translation adjustment and are included in Accumulated Other Comprehensive Loss. Foreign currency transaction gains and losses are recorded in other income, net in the accompanying statements of operations.
Identifiable intangible assets	Identifiable intangible assets The Company's identifiable intangible assets represent intangible assets acquired in the Brink Acquisition, the Drive-Thru Acquisition, the Restaurant Magic Acquisition and software development costs. The Company capitalizes certain software development costs for software used in its Restaurant/Retail reporting segment. Software development costs incurred prior to establishing technological feasibility are charged to operations and included in research and development costs. The technological feasibility of a software product is established when the Company has completed all planning, designing, coding, and testing activities that are necessary to establish that the software product meets its design specifications, including functionality, features, and technical performance requirements. Software development costs incurred after establishing technological feasibility for software sold as a perpetual license, (as defined within ASC 985-20, Software – "Costs of Software to be sold, Leased, or Marketed" - for software cost related to sold as a perpetual license) are capitalized and amortized on a product-by-product basis when the software product is available for general release to customers. Included in "Acquired and internally developed software costs" in the table below are approximately $2.5 million and $3.0 million of costs related to software products that have not satisfied the general release threshold as of December 31, 2019 and December 31, 2018, respectively. These software products are expected to satisfy the general release threshold within the next 12 months. Software development is also capitalized in accordance with ASC 350-40, “Intangibles - Goodwill and Other - Internal - Use Software,” and is amortized over the expected benefit period, which generally ranges from three to seven years. Long-lived assets are tested for impairment when events or conditions indicate that the carrying value of an asset may not be fully recoverable from future cash flows. The Company has tested for impairment of indefinite lived intangible assets during the fourth quarter of its fiscal year. To value the indefinite lived intangible assets, the Company utilizes the royalty method to estimate the fair values of the trademarks and trade names. Annual amortization charged to cost of sales when a product is available for general release to customers is computed using the greater of (a) the straight-line method over the remaining estimated economic life of the product, generally three to seven years or (b) the ratio that current gross revenues for a product bear to the total of current and anticipated future gross revenues for that product.
Stock-based compensation	Stock-based compensation The Company recognizes all stock-based compensation to employees, including awards of employee stock options and restricted stock, in the financial statements as compensation cost over the applicable vesting periods using a straight-line expense recognition method, based on their fair value on the date of grant.
Loss per share	Loss per share Basic loss per share are computed based on the weighted average number of common shares outstanding during the period. Diluted earnings/loss per share reflect the dilutive impact of outstanding stock options and restricted stock awards.
Goodwill	Goodwill The Company tests goodwill for impairment on an annual basis, which is on the first day of the fourth quarter, or more often if events or circumstances indicate there may be impairment. The Company operates in two reportable operating segments, which are the reporting units used in the test for goodwill impairment - Restaurant/Retail and Government. Goodwill impairment testing is performed at the sub-segment level (referred to as a reporting unit). Goodwill is assigned to reporting units at the date the goodwill is initially recorded. Once goodwill has been assigned to a reporting unit, it no longer retains its association with a particular acquisition, and all of the activities within a reporting unit, whether acquired or organically grown, are available to support the value of the goodwill. Goodwill impairment analysis is a two-step test. The first step, used to identify potential impairment, involves comparing each reporting unit’s fair value to its carrying value including goodwill. If the fair value of a reporting unit exceeds its carrying value, applicable goodwill is considered not to be impaired. If the carrying value exceeds fair value, there is an indication of impairment, at which time a second step would be performed to measure the amount of impairment. The second step involves calculating an implied fair value of goodwill for each reporting unit for which the first step indicated an impairment. We utilize different methodologies in performing the goodwill impairment test for each reporting unit. For both the Restaurant/Retail and Government reporting units, these methodologies include an income approach, namely a discounted cash flow method, and multiple market approaches and the guideline public company method and quoted price method. The valuation methodologies and weightings used in the current year are generally consistent with those used in our past annual impairment tests. The discounted cash flow method derives a value by determining the present value of a projected level of income stream, including a terminal value. This method involves the present value of a series of estimated future cash flows at the valuation date by the application of a discount rate, one which a prudent investor would require before making an investment in our equity. We consider this method to be most reflective of a market participant’s view of fair value given the current market conditions, as it is based on our forecasted results and, therefore, established this method's weighting at 80% of the fair value calculation. Key assumptions within our discounted cash flow model include projected financial operating results, a long-term growth rate of 3% and, depending on the reporting unit, discount rates ranging from 13.0% to 22.0%. As stated above, because the discounted cash flow method derives value from the present value of a projected level of income stream, a modification to our projected operating results, including changes to the long-term growth rate, could impact the fair value. The present value of the cash flows is determined using a discount rate based on the capital structure and capital costs of comparable public companies, as well as company-specific risk premium, as identified by us. A change to the discount rate could impact the fair value determination. The market approach is a generally-accepted way of determining a value indication of a business, business ownership interest, security, or intangible asset by using one or more methods that compare the reporting unit to similar businesses, business ownership interests, securities or intangible assets that have been sold. There are two methodologies considered under the market approach: the public company method and the quoted price method. The public company method and quoted price method of valuation are based on the premise that pricing multiples of publicly traded companies can be used as a tool to be applied in valuing closely held companies. The mechanics of the methods require the use of the stock price in conjunction with other factors to create a pricing multiple that can be used, with certain adjustments, to apply against the reporting unit’s similar factor to determine an estimate of value for the subject company. We consider these methods appropriate because they provide an indication of fair value supported by current market conditions. We established our weighting at 10% of the fair value calculation for the public company method and quoted price method for both the Restaurant/Retail and Government reporting units. The most critical assumption underlying the market approaches we use are the comparable companies selected. Each market approach described above estimates revenue and earnings multiples based on the comparable companies selected. As such, a change in the comparable companies could have an impact on the fair value determination.
Impairment of long-lived assets	Impairment of long-lived assets The Company evaluates the accounting and reporting for the impairment of long-lived assets in accordance with the reporting requirements of ASC 360-10, Accounting for the Impairment or Disposal of Long-Lived Assets. The Company will recognize impairment of long-lived assets or asset groups if the net book value of such assets exceeds the estimated future undiscounted cash flows attributable to such assets. If the carrying value of a long-lived asset or asset group is considered impaired, a loss is recognized based on the amount by which the carrying value exceeds the fair market value of the long-lived asset or asset group for assets to be held and used, or the amount by which the carrying value exceeds the fair market value less cost to sell for assets to be sold.
Use of estimates	Use of estimates The preparation of the consolidated financial statements requires management of the Company to make a number of estimates and assumptions relating to the reported amount of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the period. Significant items subject to such estimates and assumptions include revenue recognition, stock based compensation, the recognition and measurement of assets acquired and liabilities assumed in business combinations at fair value, the carrying amount of property, plant and equipment, identifiable intangible assets and goodwill, valuation allowances for receivables, inventories and deferred income tax assets, and measurement of contingent consideration at fair value. Actual results could differ from those estimates.
Recently Issued Accounting Announcements Not Yet Adopted and Recently Adopted Accounting Pronouncements	Recently Issued Accounting Pronouncements Not Yet Adopted In June 2016, the Financial Accounting Standards Board ("FASB") issued ASU 2016-13, “Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments.” ASU 2016-13 requires the measurement of all expected credit losses for financial assets held at the reporting date, based on historical experience, current conditions, and reasonable and supportable forecasts. In addition, ASU 2016-13 amends the accounting for credit losses on available-for-sale debt securities and purchased financial assets with credit deterioration. The amendment is effective for the Company beginning with its fiscal year ending December 31, 2020, however early application is permitted for reporting periods beginning after December 15, 2018; this standard is not expected to have a material impact on the Company's consolidated financial statements. In January 2017, the FASB issued ASU 2017-04, “Intangibles - Goodwill and Other (Topic 350) - Simplifying the Test for Goodwill Impairment.” ASU 2017-04 eliminates Step 2 from the goodwill impairment test which required entities to compute the implied fair value of goodwill. Under ASU 2017-04, an entity should perform its annual or interim goodwill impairment test by comparing the fair value of a reporting unit with its carrying amount. An entity should recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value; however, the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. ASU 2017-04 became effective for the Company on January 1, 2020; it is not expected to have a material impact on the Company's consolidated financial statements. In August 2018, the FASB issued ASU 2018-13, “Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement.” ASU 2018-13 modifies the fair value measurements disclosures with the primary focus to improve effectiveness of disclosures in the notes to the financial statements that is most important to the users. The new guidance modifies the required disclosures related to the valuation techniques and inputs used, uncertainty in measurement, and changes in measurements applied. ASU 2018-13 will be effective for the Company for its fiscal year beginning after December 15, 2019 and each quarterly period thereafter. Early adoption is permitted. The Company is currently assessing the impact this new guidance may have on the Company’s consolidated financial statements and footnote disclosures. In August 2018, the FASB issued ASU 2018-15, “Intangibles – Goodwill and Other (Topic 350) - Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract.” ASU 2018-15 provides guidance on the measurement of costs for internal-use software during the design, development, and implementation stages for customers in a cloud hosting arrangement. AU 2018-15 also requires the capitalized costs associated with the design, development and implementation of cloud hosted arrangements to be amortized over the term of the hosting arrangement. ASU 2018-15 became effective for the Company on January 1, 2020; it is not expected to have a material impact on the Company's consolidated financial statements. In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes, which is intended to simplify various aspects related to accounting for income taxes. This ASU removes certain exceptions to the general principles in Topic 740 and also clarifies and amends existing guidance to improve consistent application. This ASU is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020, with early adoption permitted. We are currently assessing the impact of this standard on our combined financial statements. Recently Adopted Accounting Pronouncements In February 2016, the Financial Accounting Standards Board (FASB) issued ASU 2016-02, "Leases (Topic 842)", impacting the accounting for leases intending to increase transparency and comparability of organizations by requiring balance sheet presentation of leased assets and increased financial statement disclosure of leasing arrangements. The revised standard requires entities to recognize a liability for its lease obligations and a corresponding asset representing the right to use the underlying asset over the lease term. Lease obligations are measured at the present value of lease payments and accounted for using the effective interest method. The accounting for the leased asset differ slightly depending on whether the agreement is deemed to be a financing or operating lease. For finance leases, the leased asset is depreciated on a straight-line basis and recorded separately from the interest expense in the income statement resulting in higher expense in the earlier part of the lease term. For operating leases, the depreciation and interest expense components are combined, recognized evenly over the term of the lease, and presented as a reduction to operating income. The ASU requires that assets and liabilities be presented or disclosed separately and classified appropriately as current and noncurrent. The ASU further requires additional disclosure of certain qualitative and quantitative information related to lease agreements. The new standard was effective for the Company beginning January 1, 2019 (see Note 5 - Leases, to the unaudited interim consolidated financial statements).
Revenue recognition	In May 2014, the Financial Accounting Standards Board ("FASB") issued ASU 2014-09, Revenue from Contracts with Customers, codified as ASC Topic 606 (“ASC 606”). The FASB issued amendments to ASC 606 during 2016. ASC 606 requires additional disclosures regarding the nature, amount, timing, and uncertainty of revenue and related cash flows arising from arrangements with customers. ASC 606 is effective for annual and interim reporting periods beginning after December 15, 2017. The Company adopted the new standard effective January 1, 2018 using the modified retrospective method. In evaluating the impact of adoption, we reviewed significant open arrangements with customers for each revenue source and adoption did not have a material impact. Our revenue is derived from Software as a Service (SaaS), hardware and software sales, software activation, hardware support, installations, maintenance and professional services. ASC 606 requires us to distinguish and measure performance obligations under customer contracts. Contract consideration is allocated to all performance obligations within the arrangement or contract. Performance obligations that are determined not to be distinct are combined with other performance obligations until the combined unit is determined to be distinct and that combined unit is then recognized as revenue over time or at a point in time depending on when control is transferred. We evaluated the potential performance obligations within our Restaurant/Retail reporting segment and evaluated whether each performance obligation met the ASC 606 criteria to be considered distinct performance obligations. Revenue in the Restaurant/Retail reporting segment is recognized at a point in time for software, hardware and installations. Revenue on these items are recognized when the customer obtains control of the asset. This generally occurs upon delivery and acceptance by the customer or upon installation or delivery to a third party carrier for onward delivery to customer. Additionally, revenue in the Restaurant/Retail reporting segment relating to SaaS, Advanced Exchange programs, on-site support and other services is recognized over time as the customer simultaneously receives and consumes the benefits of the Company’s performance obligations. Our support services are stand-ready obligations that are provided over the life of the contract, generally 12 months. We offer installation services to our customers for hardware and software for which we primarily hire third-party contractors to install the equipment on our behalf. We pay the third-party contractors an installation service fee based on an hourly rate as agreed upon between us and contractor. When third-party installers are used, we determine whether the nature of our performance obligations is to provide the specified goods or services ourselves (principal) or to arrange for the third party to provide the goods or services (agent). In our customer arrangements, we are primarily responsible for providing a good or service, we have inventory risk before the good or service is transferred to the customer, and we have discretion in establishing prices. As a result, we have concluded we are the principal in the arrangement and record installation revenue on a gross basis. The support services associated with hardware and software sales are a "stand-ready obligation" satisfied over time on the basis that customer consumes and receives a benefit from having access to our support resources, when and as needed, throughout the contract term. For this reason, the support services are recognized ratably over the term since we satisfy our obligation to stand ready by performing these services each day. Our contracts typically require payment within 30 to 90 days from the shipping date or installation date, depending on our terms with the customer. The primary method used to estimate standalone selling price is the price that we charge for that good or service when we sell it separately under similar circumstances to similar customers. The Company determines standalone selling price as follows: Hardware, software, and software activation (one-time fee at the initial offering of software or SaaS) performance obligations are recognized at a stand-alone selling price based on the price at which the Company sells the particular good or service separately in similar circumstances and to similar customers. The stand-alone selling price for all other performance obligations, including pass-through hardware (such as terminals, printers, or card readers), hardware support (referred to as Advanced Exchange), installation, maintenance, software upgrades, and professional services (project management) is recognized by using an expected cost plus margin. Our revenue in the Government reporting segment is recognized over time as control is generally transferred continuously to our customers. Revenue generated by the Government reporting segment is predominantly related to services provided, however, revenue is also generated through the sale of materials, software, hardware, and maintenance. For the Government reporting segment cost plus fixed fee contract portfolio, revenue is recognized over time using costs incurred to date to measure progress toward satisfying our performance obligations. Incurred cost represents work performed, which corresponds with, and thereby best depicts, the transfer of control to the customer. Contract costs include labor, material, overhead and general & administrative expenses. Profit is recognized on the fixed fee portion of the contract as costs are incurred and invoiced. Long-term fixed price contracts and programs involve the use of various techniques to estimate total contract revenue and costs. For long-term fixed price contracts, we estimate the profit on a contract as the difference between the total estimated revenue and expected costs to complete a contract and recognize that profit over the life of the contract. Contract estimates are based on various assumptions to project the outcome of future events. These assumptions include: labor productivity and availability; the complexity of the work to be performed; the cost and availability of materials; and the performance of subcontractors. Revenue and profit in future periods of contract performance are recognized using the aforesaid assumptions and adjusting the estimate of costs to complete a contract. Once the services provided are determined to be distinct or not distinct, we evaluate how to allocate the transaction price. Generally, the Government reporting segment does not sell the same good or service to similar customers and the contract performance obligations are unique to each government solicitation. The performance obligations are typically not distinct. In cases where there are distinct performance obligations, the transaction price would be allocated to each performance obligation on a ratable basis based upon the standalone selling price of each performance obligation. Cost plus margin is used for the cost plus fixed fee contract portfolios as well as the fixed price and time & materials contracts portfolios to determine the standalone selling price. In determining when to recognize revenue, we analyze whether our performance obligations in our Government contracts are satisfied over a period of time or at a point in time. In general, our performance obligations are satisfied over a period of time. However, there may be circumstances where the latter or both scenarios could apply to a contract. We usually expect payment within 30 to 90 days from the date of service, depending on our terms with the customer. We generally expense sales commissions when incurred because the amortization period would be less than one year or the total amount of commissions would be immaterial. Commissions are recorded in selling, general and administrative expenses (SG&A). We elected to exclude from the measurement of the transaction price all taxes assessed by governmental authorities that are both imposed on and concurrent with a specific revenue-producing transaction and collected by the Company from a customer (for example, sales, use, value added, and some excise taxes).