v3.26.1
Document and Entity Information - USD ($)
12 Months Ended
Jun. 30, 2026
Aug. 20, 2026
Dec. 31, 2025
Document Information [Line Items]      
Document Type 10-K    
Amendment Flag false    
Document Period End Date Jun. 30, 2026    
Document Fiscal Year Focus 2026    
Document Fiscal Period Focus FY    
Entity Registrant Name GREAT ELM GROUP, INC.    
Entity Central Index Key 0001831096    
Current Fiscal Year End Date --06-30    
Entity Well-known Seasoned Issuer No    
Entity Current Reporting Status Yes    
Entity Voluntary Filers No    
Entity Filer Category Non-accelerated Filer    
Entity Common Stock, Shares Outstanding   31,094,890  
Entity Public Float     $ 30,268,395
Entity Small Business true    
Entity Emerging Growth Company false    
Document Financial Statement Error Correction [Flag] false    
Entity Shell Company false    
Entity File Number 001-39832    
Entity Tax Identification Number 85-3622015    
Entity Address, Address Line One 3801 PGA Boulevard    
Entity Address, Address Line Two Suite 603    
Entity Address, City or Town Palm Beach Gardens    
Entity Address, State or Province FL    
Entity Address, Postal Zip Code 33410    
City Area Code 617    
Local Phone Number 375-3006    
Document Annual Report true    
Entity Incorporation, State or Country Code DE    
Entity Interactive Data Current Yes    
Document Transition Report false    
ICFR Auditor Attestation Flag false    
Auditor Name Deloitte & Touche LLP    
Auditor Firm ID 34    
Auditor Location Boston, Massachusetts    
Auditor Opinion [Text Block]

Opinion on the Financial Statements

We have audited the accompanying consolidated balance sheets of Great Elm Group, Inc. and subsidiaries (the "Company") as of June 30, 2026 and 2025, the related consolidated statements of operations, stockholders’ equity, and cash flows, for the years ended June 30, 2026 and 2025, and the related notes (collectively referred to as the "financial statements"). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Company as of June 30, 2026 and 2025, and the results of its operations and its cash flows for the years ended June 30, 2026 and 2025, in conformity with accounting principles generally accepted in the United States of America.

   
Documents Incorporated by Reference

Portions of the definitive proxy statement for the annual meeting of stockholders of the Registrant, to be filed with the Securities and Exchange Commission within 120 days of our fiscal year ended June 30, 2026, are incorporated by reference into Part III of this report.

   
Common Stock      
Document Information [Line Items]      
Title of each class Common stock, par value $0.001 per share    
Trading Symbol GEG    
Security Exchange Name NASDAQ    
7.25% Notes due 2027      
Document Information [Line Items]      
Title of each class 7.25% Notes due 2027    
Trading Symbol GEGGL    
Security Exchange Name NASDAQ