Summary of Significant Accounting Policies - Narrative (Details) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Nov. 04, 2019
Finite-Lived Intangible Assets [Line Items]
Advertising expense		$ 14,300,000	$ 15,200,000	$ 15,500,000
Fair value of projected benefit obligations	$ 12,675,000	$ 12,675,000	$ 11,519,000
Stock repurchase amount authorized					$ 80,000,000
Share repurchases (in shares)	200,410
Stock repurchased during period (in dollars per share)	$ 36.08
Common stock, par value (in dollars per share)	$ 0	$ 0	$ 0
Ntelos Holding, Corp | Pension Plan
Finite-Lived Intangible Assets [Line Items]
Fair value of pension plan assets	$ 24,100,000	$ 24,100,000	$ 20,700,000
Fair value of projected benefit obligations	$ 30,900,000	$ 30,900,000	$ 25,800,000
Discount rate	3.16%	3.16%	4.18%
Wireless
Finite-Lived Intangible Assets [Line Items]
Advertising expense		$ 10,800,000	$ 12,600,000	$ 13,500,000
nTelos Pension Plan
Finite-Lived Intangible Assets [Line Items]
Pension benefits, vesting period		5 years
Vesting reductions, threshold age of recipient		65 years
Fair value of projected benefit obligations	$ 6,824,000	$ 6,824,000	5,131,000
OPEB Plan
Finite-Lived Intangible Assets [Line Items]
Fair value of projected benefit obligations	$ 3,573,000	$ 3,573,000	$ 3,193,000
Discount rate	3.12%	3.12%	4.15%