Annual report pursuant to Section 13 and 15(d)

Leases (Details)

v3.20.4
Leases (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2018
Lessee, Lease, Description [Line Items]    
Rental expenses   $ 1.0
GCI Holdings    
Lessee, Lease, Description [Line Items]    
Lessee, Operating Lease, Existence of Option to Extend [true false] true  
Lessee, Operating Lease, Existence of Option to Terminate [true false] true  
GCI Holdings | Minimum    
Lessee, Lease, Description [Line Items]    
Lease term (in years) 1 year  
Operating lease, renewal term 5 years  
Termination period 30 days  
GCI Holdings | Maximum    
Lessee, Lease, Description [Line Items]    
Lease term (in years) 30 years  
Operating lease, renewal term 38 years  
Termination period 17 years