Pension Plan and Other Postretirement Benefits - Benefit Obligation (Details) - NTELOS Holdings Corp. [Member] - USD ($) $ in Thousands	5 Months Ended
	Sep. 30, 2016	May 06, 2016
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets, at acquisition		$ 22,813
Defined Benefit Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligations, at acquisition		37,443
Fair value of plan assets, at acquisition		22,813
Funded status:
Net pension income (expense) since acquisition date	$ 39
Total liability, at acquisition	(14,591)	(14,630)
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligations, at acquisition		4,568
Fair value of plan assets, at acquisition		0
Funded status:
Net pension income (expense) since acquisition date	(79)
Total liability, at acquisition	$ (4,647)	$ (4,568)