v3.26.1
Cover
Mar. 25, 2026
Apr. 21, 2023
Cover [Abstract]    
Document Type 8-K  
Document Period End Date Mar. 25, 2026  
Entity Registrant Name Anterix Inc.  
Entity Incorporation, State or Country Code DE  
Entity File Number 001-36827  
Entity Tax Identification Number 33-0745043  
Entity Address, Address Line One 3 Garret Mountain Plaza  
Entity Address, Address Line Two Suite 401  
Entity Address, City or Town Woodland Park  
Entity Address, State or Province NJ  
Entity Address, Postal Zip Code 07424  
City Area Code 973  
Local Phone Number 771-0300  
Written Communications   false
Soliciting Material   false
Pre-commencement Tender Offer   false
Pre-commencement Issuer Tender Offer   false
Title of 12(b) Security Common Stock, $0.0001 par value  
Trading Symbol ATEX  
Entity Emerging Growth Company false  
Amendment Flag false  
Entity Central Index Key 0001304492  
Security Exchange Name NASDAQ  
Document Information [Line Items]    
Document Type 8-K  
Document Period End Date Mar. 25, 2026  
Amendment Flag false  
Entity Central Index Key 0001304492