v3.26.1
Document And Entity Information - USD ($)
 12 Months Ended
Jun. 30, 2026
Aug. 21, 2026
Dec. 31, 2025
Document And Entity Information      
Document Type 10-K    
Amendment Flag false    
Document Annual Report true    
Document Transition Report false    
Document Period End Date Jun. 30, 2026    
Entity File Number 0-10004    
Entity Registrant Name NAPCO SECURITY TECHNOLOGIES, INC    
Entity Incorporation, State or Country Code DE    
Entity Tax Identification Number 11-2277818    
Entity Address, Address Line One 333 Bayview Avenue    
Entity Address, City or Town Amityville    
Entity Address, State or Province NY    
Entity Address, Postal Zip Code 11701    
City Area Code 631    
Local Phone Number 842-9400    
Document Fiscal Year Focus 2026    
Document Fiscal Period Focus FY    
Title of 12(b) Security Common Stock, par value $0.01 per share    
Trading Symbol NSSC    
Security Exchange Name NASDAQ    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Interactive Data Current Yes    
Entity Current Reporting Status Yes    
Entity Filer Category Large Accelerated Filer    
Entity Small Business false    
Entity Emerging Growth Company false    
Entity Shell Company false    
Entity Central Index Key 0000069633    
Current Fiscal Year End Date --06-30    
ICFR Auditor Attestation Flag true    
Document Financial Statement Error Correction [Flag] false    
Entity Public Float     $ 1,421,890,270
Entity Common Stock, Shares Outstanding   35,768,437  
Documents Incorporated by Reference [Text Block]

Portions of the registrant’s proxy statement to be filed with the Securities and Exchange Commission pursuant to Regulation 14A in connection with the registrant’s 2026 Annual Meeting of Stockholders, which will be filed subsequent to the date hereof, are incorporated by reference into Part III of this Form 10-K. Such proxy statement will be filed with the Securities and Exchange Commission not later than 120 days following the end of the registrant’s fiscal year ended June 30, 2026.

    
Auditor Name DELOITTE & TOUCHE LLP    
Auditor Firm ID 34    
Auditor Location Jericho, New York