Discontinued Operations (Details) - USD ($)	3 Months Ended
	Mar. 31, 2016	Jun. 30, 2015	Mar. 31, 2015	Sep. 30, 2014	Dec. 31, 2015	Jun. 30, 2014
Proceeds from Sale of Intangible Assets				$ 194,400,000
Disposal Group, Including Discontinued Operation, Intangible Assets, Noncurrent						$ 88,200,000
Prepaid rent - spectrum license	$ 16,900,000				$ 13,100,000
Gain on sale of wireless spectrum licenses	0		$ (112,600,000)
Gain on transfer of tower lease obligations and other assets		$ (15,900,000)
Selling, general and administrative	53,200,000		52,200,000
Depreciation and amortization	43,400,000		32,600,000
Amortization of deferred gain	0		(6,500,000)
Operating income	29,600,000		37,100,000
Income tax expense (benefit)	4,700,000		600,000
Net income (loss)	7,000,000		49,200,000
Restructuring Reserve, Current	900,000				900,000
Other current liabilities from discontinued operations	2,000,000				5,400,000
Discontinued Operations [Member]
Prepaid rent - spectrum license				$ 6,400,000
Gain on sale of wireless spectrum licenses	0		112,600,000.0
Revenue			4,400,000
Cost of products and services			12,000,000
Selling, general and administrative			1,300,000
Depreciation and amortization	0		28,600,000
Restructuring charges (reversals)			6,400,000
Amortization of deferred gain	0		(6,500,000)
Total operating costs and expenses			41,800,000
Operating income			(37,400,000)
Interest expense (income)			(800,000)
Income (loss) before income taxes			76,000,000
Income tax expense (benefit)			27,100,000
Net income (loss)	0		48,900,000
Restructuring Reserve, Current	1,400,000				4,700,000
Other current liabilities from discontinued operations	600,000				700,000
Total current liabilities from discontinued operations	2,000,000				$ 5,400,000
Increase (Decrease) in Prepaid Rent	0		3,200,000
Payments for Restructuring	$ (3,300,000)		$ (3,400,000)