Retirement Plans - Benefit Obligation (Details) - Ntelos Holding, Corp [Member] $ in Thousands	8 Months Ended
	Dec. 31, 2016 USD ($)
Pension Plan [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligations, at acquisition	$ 37,443
Service cost	0
Interest cost	956
Benefits paid	(340)
Actuarial gain	(3,703)
Benefit obligations as of December 31, 2016	34,356
Other Postretirement Benefit Plan [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligations, at acquisition	4,298
Service cost	18
Interest cost	108
Benefits paid	0
Actuarial gain	(174)
Benefit obligations as of December 31, 2016	$ 4,250