Summary of Significant Accounting Policies - Narrative (Details)		12 Months Ended				20 Months Ended
	Jan. 01, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($) shares	Dec. 31, 2005 shares	Dec. 31, 2017 USD ($)
Finite-Lived Intangible Assets [Line Items]
Impairment charges on long-lived assets		$ 0	$ 0	$ 0
Impairment of intangible assets, finite-lived		$ 0	0
Management fee		8.00%
Net service fee		8.60%
Management fee retained		6.00%
Advertising expense		$ 15,500,000	12,200,000	7,300,000
Net benefit from retirement plans		$ (1,388,000)	(4,396,000)	$ 0
Number of stock incentive plans		2				2
Affiliate contract expansion [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life, finite-lived intangible assets		4 years
Affiliate contract expansion [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life, finite-lived intangible assets		14 years
Favorable Leases - Wireless [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life, finite-lived intangible assets		1 year
Favorable Leases - Wireless [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life, finite-lived intangible assets		28 years
Unfavorable Leases Wireless [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life, finite-lived intangible assets		1 year
Unfavorable Leases Wireless [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life, finite-lived intangible assets		28 years
Acquired Subscribers – Cable [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life, finite-lived intangible assets		3 years
Acquired Subscribers – Cable [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life, finite-lived intangible assets		10 years
Other Intangible Assets [Member] | Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life, finite-lived intangible assets		15 years
Other Intangible Assets [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life, finite-lived intangible assets		20 years
Accounting Standards Update 2014-09 [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Finite-Lived Intangible Assets [Line Items]
Costs incurred on behalf of Sprint device financing program		$ 63,800,000
Payable to Customer, Reimbursement of Costs [Member] | Subsequent Event [Member] | Accounting Standards Update 2014-09 [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Finite-Lived Intangible Assets [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 63,500,000
Payments to Provide On-going Services [Member] | Subsequent Event [Member] | Accounting Standards Update 2014-09 [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Finite-Lived Intangible Assets [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 16,900,000
Ntelos Holding, Corp | Pension Plan [Member]
Finite-Lived Intangible Assets [Line Items]
Fair value of pension plan assets		22,600,000	24,100,000			$ 22,600,000
Fair value of projected benefit obligations		28,200,000	34,400,000			28,200,000
Funded status of retirement plans		5,600,000	$ 10,300,000			5,600,000
Net benefit from retirement plans						1,100,000
Non Vested Shares [Member]
Finite-Lived Intangible Assets [Line Items]
Compensation, nonvested awards, compensation cost not yet recognized		$ 2,500,000				$ 2,500,000
Compensation, nonvested awards, cost not yet recognized, period for recognition		2 years 6 months
The 2005 Plan [Member]
Finite-Lived Intangible Assets [Line Items]
Number of shares authorized for issuance (in shares) | shares					2,880,000
Award term for authorization of grants					10 years
The 2014 Plan [Member]
Finite-Lived Intangible Assets [Line Items]
Additional number of shares authorized for issuance (in shares) | shares				3,000,000
Management Shares [Member] | The 2014 Plan [Member] | Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Award term for authorization of grants				10 years