Acquisition of NTELOS Holdings Corporation (Details) $ / shares in Units, $ in Millions		3 Months Ended
	Aug. 11, 2015 USD ($) Customer $ / shares	Mar. 31, 2016 USD ($) Customer	Mar. 31, 2015 USD ($)	Dec. 31, 2015 USD ($)
Business Acquisition [Line Items]
Total debt outstanding		$ 785.0
Expected to drawn amount after closing of the merger		$ 100.0
NTELOS Holdings Corporation [Member]
Business Acquisition [Line Items]
Share price (in dollars per share) | $ / shares	$ 9.25
Total equity value	$ 208.0
Number of retail subscribers acquire | Customer	298,000
Total debt outstanding				$ 520.0
Number of sprint retail customers homed to sprint branded customers | Customer		280,000
Number of additional customers to serve under affiliate agreement with sprint | Customer		570,000
Term of affiliate relationship agreement with sprint		5 years
Management fee on post paid services		8.00%
Management fee on prepaid services		6.00%
Amount of retained revenue reduced by Sprint under the affiliate agreement		$ 252.0
Amount of expenses associated with acquisition		0.3	$ 0.1
NTELOS Holdings Corporation [Member] | Credit Facilities [Member]
Business Acquisition [Line Items]
Amount finance for acquisition and network upgrade by entity		960.0
NTELOS Holdings Corporation [Member] | Term Loan [Member]
Business Acquisition [Line Items]
Amount finance for acquisition and network upgrade by entity		885.0
NTELOS Holdings Corporation [Member] | Revolver [Member]
Business Acquisition [Line Items]
Amount finance for acquisition and network upgrade by entity		$ 75.0
NTELOS Holdings Corporation [Member] | Minimum [Member]
Business Acquisition [Line Items]
Expected period to reduce the retained revenues under the affiliate agreement		5 years
NTELOS Holdings Corporation [Member] | Maximum [Member]
Business Acquisition [Line Items]
Expected period to reduce the retained revenues under the affiliate agreement		6 years