v3.25.3
Stock-Based Compensation - Grants of Awards (Details) - $ / shares
shares in Thousands
9 Months Ended 12 Months Ended
Sep. 30, 2025
Dec. 31, 2024
Dec. 31, 2023
Stock-Based Compensation      
RSU's granted   96 160
Weighted average GDFV   $ 57.07 $ 86.62
Dividend rate 0.00%    
Minimum      
Stock-Based Compensation      
Vesting period 1 year 1 year  
Maximum      
Stock-Based Compensation      
Vesting period 5 years 5 years  
Series A and B GCI Group common stock      
Stock-Based Compensation      
RSU's granted 0    
Time-based restricted stock units | Share-based payment arrangement, employee | GCI employees | Series C GCI Group common stock      
Stock-Based Compensation      
RSU's granted 105    
Weighted average GDFV $ 37.85    
Time-based restricted stock units | Share-based payment arrangement, employee | GCI employees | Series C GCI Group common stock | Minimum      
Stock-Based Compensation      
Vesting period 1 year    
Time-based restricted stock units | Share-based payment arrangement, employee | GCI employees | Series C GCI Group common stock | Maximum      
Stock-Based Compensation      
Vesting period 3 years    
Performance based restricted stock units | Share-based payment arrangement, employee | GCI employees | Series C GCI Group common stock      
Stock-Based Compensation      
RSU's granted 59    
Weighted average GDFV $ 37.85    
Performance based restricted stock units | Share-based payment arrangement, employee | Chief executive officer | Series C GCI Group common stock      
Stock-Based Compensation      
RSU's granted 18    
Weighted average GDFV $ 37.85    
Share-based payment arrangement, option | Share-based payment arrangement, employee | Chief executive officer | Series C GCI Group common stock      
Stock-Based Compensation      
Grant of options to purchase 814    
Weighted average grant date fair value $ 12.35    
Share-based payment arrangement, option | Share-based payment arrangement, employee | Chief executive officer | Series C GCI Group common stock | Dec 31, 2026      
Stock-Based Compensation      
Award vesting rights, percentage 0.33%    
Share-based payment arrangement, option | Share-based payment arrangement, employee | Chief executive officer | Series C GCI Group common stock | Dec 31, 2027      
Stock-Based Compensation      
Award vesting rights, percentage 0.33%    
Share-based payment arrangement, option | Share-based payment arrangement, employee | Chief executive officer | Series C GCI Group common stock | Dec 31, 2028      
Stock-Based Compensation      
Award vesting rights, percentage 0.33%    
Share-based payment arrangement, option | Share-based payment arrangement, non-employee | Non-employee directors | Series C GCI Group common stock      
Stock-Based Compensation      
Weighted average GDFV $ 11.53    
Grant of options to purchase 33