v3.26.3
Earnings per Share - Additional Information (Details) - shares
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Jun. 30, 2025
Jun. 30, 2026
Apr. 01, 2026
Dec. 31, 2025
Dec. 31, 2024
HMH Holding B.V. And Subsidiaries            
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]            
Common stock, shares outstanding (in shares)     63,783,304   200 200
Class A Common Stock            
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]            
Shares issuable (in shares)     31,891,652      
Class A Common Stock | IPO            
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]            
Number of shares issued in 2026 that are excluded from calculation of basis and diluted EPS in 2025 11,200,000 11,200,000        
Class A Common Stock | HMH Holding B.V. And Subsidiaries            
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]            
Common stock, shares outstanding (in shares)     12,042,625 100 100  
Class B Common Stock            
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]            
Common stock, shares outstanding (in shares)     31,891,652      
Class B Common Stock | HMH Holding B.V. And Subsidiaries            
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]            
Common stock, shares outstanding (in shares)     31,891,652 100   100