Revenue Recognition - Summary of Disaggregation of Revenue Qualitative Reconciliation (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Disaggregation of Revenue [Line Items]
Total revenues	$ 279,254	$ 269,681
High Speed Data [Member]
Disaggregation of Revenue [Line Items]
Total revenues	109,436	97,501
Video [Member]
Disaggregation of Revenue [Line Items]
Total revenues	103,195	107,672
Phone [Member]
Disaggregation of Revenue [Line Items]
Total revenues	15,918	15,149
Business services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	42,350	40,153
Advertising [Member]
Disaggregation of Revenue [Line Items]
Total revenues	$ 8,355	$ 9,206