Quarterly report pursuant to Section 13 or 15(d)

Basis of Presentation (Details)

v3.8.0.1
Basis of Presentation (Details) - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended
Dec. 31, 2015
Sep. 30, 2017
Sep. 30, 2016
Sep. 30, 2017
Sep. 30, 2016
May 18, 2016
Feb. 28, 2014
Voting interest acquired (as a percent)           25.01%  
Accounting Standards Update 2016-09              
Cumulative effect of accounting change at Charter   $ 17,361   $ 17,361      
Liberty              
Related Party Transaction, Amounts of Transaction   $ 814 $ 661 $ 2,400 $ 2,400    
Skyhook | Skyhook Wireless, Inc.              
Voting interest acquired (as a percent)             100.00%
Customer concentration | Revenue              
Concentration Risk, Percentage   57.00% 85.00% 57.00% 64.00%    
Customer concentration | Revenue | Minimum | Skyhook              
Concentration Risk, Percentage 80.00%            
Customer concentration | Revenue | Maximum | Skyhook              
Concentration Risk, Percentage 90.00%