Long-Term Debt - Narrative (Details)		1 Months Ended		12 Months Ended
	Dec. 18, 2015 USD ($) facility	Sep. 30, 2018 USD ($)	Jan. 31, 2017 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Debt Instrument [Line Items]
Number of credit facilities | facility	3
Proceeds from revolving credit facility borrowings				$ 15,000,000	$ 0	$ 0
Total debt, net of unamortized loan fees				770,242,000	821,958,000
Unamortized loan fees				$ 14,994,000	$ 14,542,000
Weighted average interest rate				3.97%
Total leverage ratio through December 30, 2019	3.25
Total leverage ratio thereafter	3.00
Debt service coverage ratio, actual				3.63
Minimum liquidity balance	$ 25,000,000			$ 25,000,000
Accrued in anticipation of early distribution of patronage credit				$ 2,800,000
Percentage of patronage credit paid in cash				75.00%
Percentage of patronage credit paid in shares				25.00%
One-time cash distribution from CoBank		$ 200,000
London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Fixed interest rate	1.16%
Maximum
Debt Instrument [Line Items]
Amended 2016 Credit Agreement, limit of dividends paid, distributions and redemption of capital stock				$ 25,000,000
Amended 2016 Credit Agreement, limit of consolidated net income (as a percent)				60.00%
Total leverage ratio from closing date through December 30, 2018	3.50
Minimum
Debt Instrument [Line Items]
Debt service coverage ratio, actual	2.00
Revolving Credit Facility
Debt Instrument [Line Items]
Term of credit facility	5 years
Maximum borrowing capacity	$ 75,000,000
Incremental Term Loan Facility
Debt Instrument [Line Items]
Number of credit facilities | facility	1
Maximum borrowing capacity	$ 150,000,000
Amended 2016 Credit Agreement
Debt Instrument [Line Items]
Shift in principal amount from Term Loan A-1 to Term Loan A-2				$ 108,800,000
Term loan A-1
Debt Instrument [Line Items]
Term of credit facility	5 years
Maximum borrowing capacity	$ 485,000,000
Quarterly principal payment period one				3,600,000
Quarterly principal payment period two				7,300,000
Quarterly principal payment period three				$ 10,900,000
Term loan A-1 | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate	2.75%			1.75%
Term loan A-1 | Ntelos Holding, Corp
Debt Instrument [Line Items]
Line of credit facility amount borrowed	$ 485,000,000
Term loan A-2
Debt Instrument [Line Items]
Term of credit facility	7 years
Maximum borrowing capacity	$ 400,000,000
Proceeds from revolving credit facility borrowings			$ 25,000,000			$ 50,000,000
Quarterly principal payment period one				$ 1,200,000
Term loan A-2 | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate	3.00%			2.00%
Term loan A-2 | Ntelos Holding, Corp
Debt Instrument [Line Items]
Line of credit facility amount borrowed	$ 325,000,000
Term loan A-2 | Delayed Draw Term Loan
Debt Instrument [Line Items]
Line of credit facility remaining borrowing capacity	$ 75,000,000			$ 75,000,000