v3.8.0.1
Document and Entity Information - USD ($)
12 Months Ended
Dec. 31, 2017
Feb. 23, 2018
Jun. 30, 2017
Document Type 10-K    
Document Period End Date Dec. 31, 2017    
Amendment Flag false    
Entity Registrant Name GCI LIBERTY, INC.    
Entity Central Index Key 0000808461    
Entity Current Reporting Status Yes    
Entity Voluntary Filers No    
Current Fiscal Year End Date --12-31    
Entity Filer Category Accelerated Filer    
Entity Well-known Seasoned Issuer No    
Document Fiscal Year Focus 2017    
Document Fiscal Period Focus FY    
Entity Public Float     $ 533,981,114
Class A-1 Common Stock      
Entity Common Stock Shares Outstanding   32,848,000  
Class B-1 Common Stock      
Entity Common Stock Shares Outstanding   3,047,000