Acquisitions and Dispositions (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Jun. 11, 2010 Cyrus Networks [Member]
Business Acquisition, Cost of Acquired Entity, Purchase Price [Abstract]
Business Acquisition, Cost of Acquired Entity, Purchase Price				$ 526
Business Acquisition, Purchase Price Allocation [Abstract]
Receivables				10.4
Other current assets				0.5
Property, plant and equipment				153.6
Goodwill				269.6
Intangible assets				138.0
Other noncurrent assets				0.1
Total assets acquired				572.2
Accounts payable				3.1
Unearned revenue and customer deposits				7.7
Accrued taxes				1.5
Accrued payroll and benefits				0.7
Other current liabilities				0.8
Noncurrent liabilities				32.1
Total liabilities assumed				45.9
Net assets acquired				526.3
Business Acquisition, Pro Forma Information [Abstract]
Revenue			1,408.6
Net income			23.3
Basic earnings per common share			$ 0.06
Diluted earnings per common share			$ 0.06
Disposition of Assets [Abstract]
Proceeds from sale of assets	1.6	11.5	0
Gain on sale of assets	$ 1.6	$ 8.4	$ 0