Description of Business and Summary of Significant Accounting Policies - Narrative (Details) shares in Thousands		12 Months Ended
	Oct. 01, 2016 USD ($)	Dec. 31, 2016 USD ($) state shares	Dec. 31, 2015 USD ($) shares	Dec. 31, 2014 USD ($) shares	Sep. 30, 2016 USD ($)	May 06, 2016 USD ($)
Accounting Policies [Abstract]
Non Sprint operations, number of states | state		4
Cash equivalents			$ 40,100,000
Goodwill impairment	$ 0
Asset retirement obligations, current portion			0		$ 5,841,000
Indefinite-lived Intangible Assets [Line Items]
Carrying value		$ 64,431,000	64,098,000
Amortization expense		$ 34,900,000	$ 1,400,000	$ 2,600,000
Management fee		8.00%
Net service fee		8.60%
Management fee retained		6.00%
Period for sprint's waiver of the management fee		6 years
Contract term		14 years
Stock options outstanding (in shares) | shares		911	1,312	1,394
Antidilutive shares and options excluded from computation of earnings per share (in shares) | shares			92	22
Deferred income taxes		$ 0	$ 907,000
Excess tax benefits recognized as discrete items		1,709,000	0	$ 0
Ntelos Holding, Corp [Member]
Indefinite-lived Intangible Assets [Line Items]
Unamortized loan fees and costs reclassification						$ 23,000,000
Accounting Standards Update 2015-03 [Member] | Assets [Member]
Indefinite-lived Intangible Assets [Line Items]
Unamortized loan fees and costs reclassification			(1,600,000)
Accounting Standards Update 2015-03 [Member] | Assets [Member] | Ntelos Holding, Corp [Member]
Indefinite-lived Intangible Assets [Line Items]
Unamortized loan fees and costs reclassification			(4,300,000)
Accounting Standards Update 2015-03 [Member] | Other Assets [Member]
Indefinite-lived Intangible Assets [Line Items]
Unamortized loan fees and costs reclassification			(1,600,000)
Accounting Standards Update 2015-03 [Member] | Other Assets [Member] | Ntelos Holding, Corp [Member]
Indefinite-lived Intangible Assets [Line Items]
Unamortized loan fees and costs reclassification			(4,300,000)
Accounting Standards Update 2015-03 [Member] | Liabilities and Equity [Member]
Indefinite-lived Intangible Assets [Line Items]
Unamortized loan fees and costs reclassification			1,600,000
Accounting Standards Update 2015-03 [Member] | Liabilities and Equity [Member] | Ntelos Holding, Corp [Member]
Indefinite-lived Intangible Assets [Line Items]
Unamortized loan fees and costs reclassification			4,300,000
Accounting Standards Update 2015-03 [Member] | Long-term Debt, Current Maturities [Member]
Indefinite-lived Intangible Assets [Line Items]
Unamortized loan fees and costs reclassification			500,000
Accounting Standards Update 2015-03 [Member] | Long-term Debt [Member]
Indefinite-lived Intangible Assets [Line Items]
Unamortized loan fees and costs reclassification			1,100,000
Accounting Standards Update 2015-03 [Member] | Long-term Debt [Member] | Ntelos Holding, Corp [Member]
Indefinite-lived Intangible Assets [Line Items]
Unamortized loan fees and costs reclassification			4,300,000
Cable Franchise Rights [Member]
Indefinite-lived Intangible Assets [Line Items]
Impairment of intangible assets		0	0	$ 0
Carrying value		64,334,000	64,059,000
Fair value amount exceeding the carrying amount		$ 28,200,000	$ 11,300,000