Nature of Operations and Basis of Presentation	3 Months Ended
Nature of Operations and Basis of Presentation	Jun. 30, 2023
Accounting Policies [Abstract]
Nature of Operations and Basis of Presentation	Nature of Operations and Basis of Presentation Anterix Inc. (the “Company”) is a wireless communications company focused on commercializing its spectrum assets to enable its targeted utility and critical infrastructure customers to deploy private broadband networks and on offering innovative broadband solutions to the same target customers. The Company is the largest holder of licensed spectrum in the 900 MHz band (896 - 901 / 935 - 940 MHz) with nationwide coverage throughout the contiguous United States, Hawaii, Alaska and Puerto Rico. On May 13, 2020, the Federal Communications Commission (the “FCC”) approved the Report and Order (the “Report and Order”) to modernize and realign the 900 MHz band to increase its usability and capacity by allowing it to be utilized for the deployment of broadband networks, technologies and solutions. The Report and Order was published in the Federal Register on July 16, 2020, and became effective on August 17, 2020. The Company is now engaged in qualifying for and securing broadband licenses from the FCC. At the same time, the Company is pursuing opportunities to monetize the broadband spectrum it secures to its targeted utility and critical infrastructure customers. The Company is also expanding the benefits and solutions it offers to the same targeted customers. As part of the Company’s expanded offerings, the Company launched an integrated platform to accelerate the scale benefits of combining, or networking together, individual private broadband networks, added a public network roaming management solution, and is currently offering CatalyX as a turnkey connectivity management solution that helps utilities realize the benefits of private broadband networks while leveraging commercial broadband during their transition to private LTE (“PLTE”) networks. Business Developments In April 2023, the Company entered into an agreement with Lower Colorado River Authority (“LCRA”) to sell 900 MHz Broadband Spectrum covering 68 counties and more than 30 cities in LCRA’s wholesale electric, transmission, and water service area (the “LCRA Agreement”) for total payments of $30.0 million plus the contribution of select LCRA 900 MHz narrowband spectrum. The LCRA Agreement will support LCRA’s deployment of a PLTE network which will provide a host of capabilities including grid awareness, communications and operational intelligence that will enhance resilience and spur innovation at LCRA. The new licenses will enable LCRA to move from narrowband to next generation broadband and provide mission-critical data and voice services within LCRA and to more than 100 external customers such as electric cooperatives, schools and transit authorities across more than 73,000 square miles. The payment of $30.0 million is due through fiscal year 2026 as the Company delivers the relevant cleared 900 MHz Broadband Spectrum and the associated broadband licenses to LCRA. The LCRA Agreement is subject to customary provisions regarding remedies for non-delivery, including refund of amounts paid and termination rights if the Company fails to perform its contractual obligations, including failure to deliver the relevant cleared 900 MHz Broadband Spectrum in accordance with the terms of the LCRA Agreement. A gain or loss on the sale of spectrum will be recognized for each county once the Company delivers the cleared 900 MHz Broadband Spectrum and the associated broadband licenses to LCRA in full. Basis of Presentation and Use of Estimates The consolidated financial statements and accompanying notes are prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) for interim financial information. Pursuant to the rules and regulations of the U.S. Securities and Exchange Commission (the “SEC”), certain information and footnote disclosures normally included in annual consolidated financial statements prepared in accordance with U.S. GAAP have been condensed or omitted, these unaudited consolidated financial statements should be read in conjunction with the audited consolidated financial statements and related notes in the Company’s Annual Report on Form 10-K for the fiscal year ended March 31, 2023, filed with the SEC on June 14, 2023 (the “2023 Annual Report”). In the Company’s opinion all normal and recurring adjustments considered necessary for a fair presentation of the financial position, results of operations and cash flows for the periods presented have been included. The Company believes that the disclosures made in the unaudited consolidated interim financial statements are adequate to make the information not misleading. The results of operations for the interim periods presented are not necessarily indicative of the results for the year. The Company is also required to make certain estimates and assumptions that affect the report amounts. These estimates and assumptions are reviewed periodically, and the effects of revisions are reflected in the financial statements in the applicable period. Accordingly, actual results could materially differ from those estimates. The accompanying consolidated financial statements include the accounts of the Company and its subsidiaries. All significant intercompany accounts and transactions have been eliminated in consolidation. Recently Issued Accounting Pronouncements While there have been accounting standards that have been issued or proposed by the FASB or other standard-setting bodies that do not require adoption until a future date, these updates are not expected to have a material impact on the Company’s consolidated financial statements upon adoption.