Discontinued Operations (Details) - USD ($)	3 Months Ended				9 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Apr. 01, 2015	Dec. 31, 2014
Proceeds from Sale of Intangible Assets				$ 194,400,000	$ 0	$ 194,400,000
Indefinite-Lived Intangible Assets (Excluding Goodwill)				88,200,000		88,200,000
Gain on Liabilities and Other Assets transferred in Sale of Business Affiliate and Productive Assets		$ (15,900,000)			(15,900,000)	0
Property, plant and equipment, net	$ 930,400,000				930,400,000			$ 815,400,000
Current portion of long-term debt	12,400,000				12,400,000			11,600,000
Selling, General and Administrative Expense	52,500,000			52,900,000	161,700,000	151,700,000
Depreciation and amortization	35,800,000			32,300,000	102,400,000	94,400,000
Restructuring charges (reversals)	300,000	2,300,000	$ 3,400,000	(1,300,000)	6,000,000	(100,000)
Transaction costs	800,000			200,000	800,000	900,000
Amortization of deferred gain					6,500,000	16,500,000
Operating income	36,200,000			47,800,000	103,000,000	145,500,000
Other Nonoperating Income (Expense)	(400,000)			0	(800,000)	1,200,000
Gain on sale of wireless spectrum licenses					(112,600,000)	0
Income tax expense (benefit)	44,100,000			1,200,000	146,100,000	83,100,000
Net income	80,300,000			(27,300,000)	321,100,000	93,900,000
Prepaid Expense, Current	13,800,000				13,800,000			10,800,000
Disposal Group, Including Discontinued Operation, Other Assets, Current	0				0			4,700,000
Disposal Group, Including Discontinued Operation, Other Assets, Noncurrent	0				0			44,600,000
Other noncurrent liabilities	41,400,000				41,400,000			26,200,000
Restructuring Reserve, Current	1,200,000				1,200,000			4,900,000
Other current liabilities from discontinued operations	11,900,000				11,900,000			142,000,000
Restructuring Reserve, Noncurrent	300,000				300,000
Other noncurrent liabilities from discontinued operations	0				0			102,700,000
Liabilities	1,783,500,000				1,783,500,000			2,469,200,000
Payments to Acquire Property, Plant, and Equipment	73,200,000			45,300,000	205,700,000	121,100,000
Payments for Restructuring	(1,400,000)	$ (3,500,000)	$ (4,500,000)
Continuing Operations [Member]
Long-term Debt, Current Maturities	1,200,000				1,200,000			1,100,000
Long-term Debt, Excluding Current Maturities	52,400,000				52,400,000			57,000,000
Net income	79,300,000			(7,500,000)	260,300,000	122,100,000
Other noncurrent liabilities	8,200,000				8,200,000			7,500,000
Liabilities	61,800,000				61,800,000			65,600,000
Payments to Acquire Property, Plant, and Equipment						114,600,000
Discontinued Operations [Member]
Proceeds from Sale of Intangible Assets					0	194,400,000
Gain on Liabilities and Other Assets transferred in Sale of Business Affiliate and Productive Assets	0			0	15,900,000	0
Property, plant and equipment, net							$ 16,000,000
Current portion of long-term debt							500,000
Long-term debt, less current portion							24,800,000
Other non-current liabilities	0				0		6,600,000	8,000,000
Total Liabilities	11,900,000				11,900,000		$ 31,900,000	244,700,000
Revenue	0			30,100,000	4,400,000	116,000,000
Cost of products and services	0			13,700,000	12,000,000	53,200,000
Selling, General and Administrative Expense	0			4,900,000	2,200,000	16,300,000
Depreciation and amortization	0			29,100,000	28,600,000	74,200,000
Restructuring charges (reversals)	(2,100,000.0)			10,300,000	4,300,000	15,500,000
Asset Impairment Charges	0			7,500,000	0	7,500,000
Transaction costs	0			2,800,000	0	2,800,000
Amortization of deferred gain	0			(6,400,000)	(6,500,000)	(16,500,000)
Operating Costs and Expenses	(2,100,000)			61,900,000	40,600,000	153,000,000
Operating income	2,100,000			(31,800,000)	(36,200,000)	(37,000,000)
Interest Income (Expense), Net	0			1,100,000	(1,700,000)	3,800,000
Other Nonoperating Income (Expense)	(100,000)			(200,000)	(200,000)	1,700,000
Gain on sale of wireless spectrum licenses	0			0	112,600,000	0
Long-term Debt, Current Maturities	0				0			1,600,000
Long-term Debt, Excluding Current Maturities	0				0			81,600,000
Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax	2,200,000			(32,700,000)	94,200,000	(42,500,000)
Income tax expense (benefit)	1,200,000			(12,900,000)	33,400,000	(14,300,000)
Net income	1,000,000			(19,800,000)	60,800,000	(28,200,000)
Prepaid Expense, Current	0			$ 6,400,000	0	6,400,000		3,200,000
Disposal Group, Including Discontinued Operation, Other Assets, Current	0				0			1,500,000
Disposal Group, Including Discontinued Operation, Assets, Current	0				0			4,700,000
Disposal Group, Including Discontinued Operation, Property, Plant and Equipment	0				0			44,100,000
Disposal Group, Including Discontinued Operation, Other Assets, Noncurrent	0				0			500,000
Disposal Group, Including Discontinued Operation, Assets, Noncurrent	0				0			44,600,000
Disposal Group, Including Discontinued Operation, Assets	0				0			49,300,000
Accounts Payable	200,000				200,000			5,000,000
Restructuring Reserve, Current	8,900,000				8,900,000			15,400,000
Deferred Gain on Sale of Property	0				0			112,600,000
Other current liabilities from discontinued operations	2,800,000				2,800,000			7,400,000
Disposal Group, Including Discontinued Operation, Liabilities, Current	11,900,000				11,900,000			142,000,000
Restructuring Reserve, Noncurrent	0				0			0
Other noncurrent liabilities from discontinued operations	0				0			102,700,000
Increase (Decrease) in Prepaid Rent					3,200,000	0
Payments to Acquire Property, Plant, and Equipment					0	(6,500,000)
Payments for Restructuring					(11,200,000)	$ (1,000,000)
Wireless Towers [Member] | Discontinued Operations [Member]
Deferred Gain on Sale of Property	$ 0				$ 0			$ 13,100,000