BASIS OF PRESENTATION (Policies)	9 Months Ended
BASIS OF PRESENTATION (Policies)	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	The accompanying unaudited interim consolidated financial statements have been prepared by NetScout Systems, Inc. (NetScout or the Company). Certain information and footnote disclosures normally included in financial statements prepared under United States generally accepted accounting principles (GAAP) have been condensed or omitted pursuant to the rules and regulations of the Securities and Exchange Commission (SEC). In the opinion of management, the unaudited interim consolidated financial statements include all adjustments, consisting of normal recurring adjustments, necessary for a fair statement of the Company's financial position, results of operations and cash flows. The year-end consolidated balance sheet data was derived from the Company's audited financial statements, but does not include all disclosures required by GAAP. The results reported in these unaudited interim consolidated financial statements are not necessarily indicative of results that may be expected for the entire year. All significant intercompany accounts and transactions are eliminated in consolidation. These unaudited interim consolidated financial statements should be read in conjunction with the audited consolidated financial statements, including the notes thereto, included in the Company’s Annual Report on Form 10-K for the fiscal year ended March 31, 2018 filed with the Securities and Exchange Commission on May 21, 2018. Certain amounts for the three and nine months ended December 31, 2017 have been reclassified to conform to the current period presentation. These reclassifications had no effect on the reported results of operations.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In August 2018, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update 2018-15, Intangibles – Goodwill and Other – Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract (ASU 2018-15). This ASU clarifies the accounting treatment for implementation costs for cloud computing arrangements (hosting arrangements) that is a service contract. This guidance is effective for fiscal years beginning after December 15, 2019, including interim periods within that fiscal year. The Company adopted ASU 2018-15 effective July 1, 2018. The adoption has had an immaterial impact to the consolidated financial statements for the nine months ended December 31, 2018. In August 2018, the FASB issued ASU 2018-14, Compensation – Retirement Benefits – Defined Benefit Plans – General (Subtopic 715-20): Disclosure Framework—Changes to the Disclosure Requirements for Defined Benefit Plans. This ASU adds, modifies and clarifies several disclosure requirements for employers that sponsor defined benefit pension or other postretirement plans. This guidance is effective for fiscal years ending after December 15, 2020. ASU 2018-14 is effective for NetScout beginning April 1, 2021. Early adoption is permitted. The Company is currently assessing the effect that ASU 2018-14 will have on its financial position, results of operations, and disclosures. In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement. ASU 2018-13 adds, modifies and removes several disclosure requirements relative to the three levels of inputs used to measure fair value in accordance with Topic 820, Fair Value Measurement. This guidance is effective for fiscal years beginning after December 15, 2019, including interim periods within that fiscal year. ASU 2018-13 is effective for NetScout beginning April 1, 2020. Early adoption is permitted. The Company is currently assessing the effect that ASU 2018-13 will have on its financial position, results of operations, and disclosures. In February 2018, the FASB issued ASU 2018-02, Reclassification of Certain Tax Effects From Accumulated Other Comprehensive Income (ASU 2018-02). ASU 2018-02 amends ASC 220, Income Statement - Reporting Comprehensive Income, to allow a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the Tax Cuts and Jobs Act (Tax Legislation). In addition, under the ASU 2018-02, the Company may be required to provide certain disclosures regarding stranded tax effects. ASU 2018-02 is effective for years beginning after December 15, 2018, and interim periods within those fiscal years. ASU 2018-02 is effective for NetScout beginning April 1, 2019. Early adoption is permitted. The Company does not believe the adoption of ASU 2018-02 will have a material impact on its consolidated financial statements. In August 2017, the FASB issued ASU 2017-12, Derivatives and Hedging (Topic 815), Targeted Improvements to Accounting for Hedging Activities (ASU 2017-12). ASU 2017-12 provides guidance to better align an entity's risk management activities and financial reporting for hedging relationships through changes to both the designation and measurement guidance for qualifying hedging relationships and the presentation of hedge results. The amendments expand and refine hedge accounting for both non-financial and financial risk components and align the recognition and presentation of the effects of the hedging instrument and the hedged item in the financial statements. This standard is effective for financial statements issued for fiscal years beginning after December 15, 2018, with early adoption permitted. ASU 2017-12 is effective for the Company beginning April 1, 2019. The Company is currently assessing the potential impact of the adoption of ASU 2017-12 on its consolidated financial statements. In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) Section A - Leases: Amendments to the FASB Accounting Standards Codification (ASU 2016-02) and issued subsequent amendments to initial guidance in July 2018 within ASU 2018-10, Codification Improvements to Topic 842, Leases and ASU 2018-11, Leases (Topic 842): Targeted Improvements (collectively, ASC 842). ASC 842 aims to increase transparency and comparability among organizations with respect to accounting for leases. Lessees will recognize a right-of-use asset and a lease liability measured at the present value of lease payments for virtually all of their leases. Short term leases with a term of 12 months or less are not required to be recognized. ASC 842 also requires disclosure of key information about leasing arrangements. ASC 842 will be effective for fiscal years beginning after December 15, 2018, including interim periods within such fiscal years. Early adoption is permitted. ASC 842 is effective for the Company beginning April 1, 2019. The Company expects to adopt the transition method, which will not require adjustments to comparative periods nor require modified disclosures in those comparative periods. The Company will apply ASC 842 at the adoption date and recognize right of use assets and lease liabilities in the period of adoption. The new standard provides a number of optional practical expedients in transition. The Company expects to elect the package of practical expedients, which among other things, allows the carryforward of the historical lease classification. Further, upon implementation of the new guidance, the Company intends to elect the practical expedients to combine lease and non-lease components, and to not recognize right-of-use assets and lease liabilities for short-term leases. The Company is in the process of identifying appropriate changes to its accounting policies, information technology systems, business processes, and related internal controls to support recognition and disclosure requirements under ASC 842. The Company expects to design any necessary changes to its business processes, controls and systems in the near future and implement the changes over the remainder of fiscal year 2019. While the Company continues to evaluate the effect of adopting this guidance on its consolidated financial statements and related disclosures, it is expected that the operating leases as disclosed in Note 17, "Commitments and Contingencies" contained in the Company’s Annual Report on Form 10-K for the fiscal year ended March 31, 2018, that do not qualify for the short term exception will be reported in the consolidated balance sheets upon adoption. As such, the Company believes the adoption of ASC 842 will have a material impact on its consolidated balance sheets. The impact on the Company's results of operations and cash flows is not expected to be material. In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers: Topic 606 (Topic 606). Topic 606 supersedes the revenue recognition requirements in Topic 605, Revenue Recognition, and requires entities to recognize revenue when control of the promised goods or services is transferred to customers at an amount that reflects the consideration to which the entity expects to be entitled to in exchange for those goods or services. The Company adopted Topic 606 as of April 1, 2018 using the modified retrospective transition method. Please refer to Note 2, "Revenue Recognition" for further details.
Revenue from Contract with Customers	Revenue from Contracts with Customers In May 2014, the FASB issued Topic 606, which requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. Topic 606 replaced most existing revenue recognition guidance under GAAP. The new standard introduces a five-step process to be followed in determining the amount and timing of revenue recognition. It also provides guidance on accounting for costs incurred to obtain or fulfill contracts with customers and establishes disclosure requirements which are more extensive than those required under prior GAAP. Topic 606 became effective for the Company on April 1, 2018. The Company elected to use the modified retrospective transition approach. Therefore, the comparative financial information has not been restated and continues to be reported under the accounting standards in effect for those periods. Revenue Recognition Policy The Company exercises judgment and uses estimates in connection with determining the amounts of product and service revenues to be recognized in each accounting period. The Company derives revenues primarily from the sale of network management tools and security solutions for service provider and enterprise customers, which include hardware, software and service offerings. The majority of its product sales consist of hardware products with embedded software that are essential to providing customers the intended functionality of the solutions. The Company also sells stand-alone software solutions to provide customers with enhanced functionality. In addition, the Company sells hardware bundled with a software license. The Company accounts for revenue once a legally enforceable contract with a customer has been approved by the parties and the related promises to transfer products or services have been identified. A contract is defined by the Company as an arrangement with commercial substance identifying payment terms, each party’s rights and obligations regarding the products or services to be transferred and the amount the Company deems probable of collection. Customer contracts may include promises to transfer multiple products and services to a customer. Determining whether the products and services are considered distinct performance obligations that should be accounted for separately or as one combined performance obligation may require significant judgment. Revenue is recognized when control of the products or services are transferred to the Company's customers, in an amount that reflects the consideration the Company expects to be entitled to in exchange for products and services. Product revenue is recognized upon shipment, provided a legally enforceable contract exists, control has passed to the customer, and in the case of software products, when the customer has the rights and ability to access the software, and collection of the related receivable is probable. If any significant obligations to the customer remain post-delivery, typically involving obligations relating to installation and acceptance by the customer, revenue recognition is deferred until such obligations have been fulfilled. The Company's service offerings include installation, integration, extended warranty and maintenance services, post-contract customer support, stand-ready software-as-a-service (SAAS) and other professional services including consulting and training. The Company generally provides software and/or hardware support as part of product sales. Revenue related to the initial bundled software and hardware support is recognized ratably over the support period. In addition, customers can elect to purchase extended support agreements for periods after the initial software/hardware warranty expiration. Support services generally include rights to unspecified upgrades (when and if available), telephone and internet-based support, updates, bug fixes and hardware repair and replacement. Consulting services are recognized upon delivery or completion of performance depending on the terms of the underlying contract. SAAS services are recognized ratably over the contract term beginning on the commencement of services. Reimbursements of out-of-pocket expenditures incurred in connection with providing consulting services are included in services revenue, with the offsetting expense recorded in cost of service revenue. Training services include on-site and classroom training. Training revenues are recognized upon delivery of the training. Generally, the Company's contracts are accounted for individually. However, when contracts are closely interrelated and dependent on each other, it may be necessary to account for two or more contracts as one to reflect the substance of the group of contracts. Bundled arrangements are concurrent customer purchases of a combination of our product and service offerings that may be delivered at various points in time. The Company allocates the transaction price among the performance obligations in an amount that depicts the relative standalone selling prices (SSP) of each obligation. Judgment is required to determine the SSP for each distinct performance obligation. The Company uses a range of amounts to estimate SSP when it sells each of the products and services separately based on the element’s historical pricing. The Company also considers its overall pricing objectives and practices across different sales channels and geographies, and market conditions. Generally, the Company has established SSP for a majority of its service elements based on historical standalone sales. In certain instances, the Company has established SSP for services based upon an estimate of profitability and the underlying cost to fulfill those services. Further, for certain service engagements, the Company considers quoted prices as part of multi-element arrangements of those engagements as a basis for establishing SSP. SSP has been established for product elements as the average or median selling price the element was recently sold for, whether sold alone or sold as part of a multiple element transaction. The Company reviews sales of the product elements on a quarterly basis and updates, when appropriate, its SSP for such elements to ensure that it reflects recent pricing experience. The Company's products are distributed through its direct sales force and indirect distribution channels through alliances with resellers and distributors. Revenue arrangements with resellers and distributors are recognized on a sell-in basis; that is, when control for the product transfers to the reseller or distributor. The Company records consideration given to a reseller or distributor as a reduction of revenue to the extent they have recorded revenue from the reseller or distributor. With limited exceptions, the Company's return policy does not allow product returns for a refund. Returns have been insignificant to date. In addition, the Company has a history of successfully collecting receivables from its resellers and distributors.