Other Long-Term Liabilities - Summary of Other Long-Term Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Other Long Term Liabilities [Line Items]
Other long-term liabilities	$ 63,622	$ 65,265
Deferred GCI Capacity Revenue, Net of Current Portion [Member]
Other Long Term Liabilities [Line Items]
Other long-term liabilities	36,299	37,338
Other Deferred IRU Capacity Revenue, Net of Current Portion [Member]
Other Long Term Liabilities [Line Items]
Other long-term liabilities	16,384	17,009
Other Deferred Revenue, Net of Current Portion [Member]
Other Long Term Liabilities [Line Items]
Other long-term liabilities	2,316	2,224
Other Long-Term Liabilities [Member]
Other Long Term Liabilities [Line Items]
Other long-term liabilities	$ 8,623	$ 8,694