Business Segment Information (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Segment Reporting Information [Line Items]
Revenue		$ 295.7	$ 249.6
Operating income (loss)		24.2	(1.8)
Expenditures for long-lived assets		32.7	55.1
Depreciation and amortization		51.2	45.8
Assets		2,186.0		$ 2,187.6
Entertainment and Communications [Member]
Segment Reporting Information [Line Items]
Revenue		174.2	175.1
Operating income (loss)		28.6	3.1
Expenditures for long-lived assets	[1]	27.6	46.8
Depreciation and amortization		40.9	39.4
Assets		1,102.5		1,111.4
IT Services and Hardware [Member]
Segment Reporting Information [Line Items]
Revenue		127.6	81.0
Operating income (loss)		1.4	0.9
Depreciation and amortization		10.2	6.4
Assets		494.4		482.7
Corporate Segment [Member]
Segment Reporting Information [Line Items]
Operating income (loss)		(5.8)	(5.8)
Depreciation and amortization		0.1	0.0
Intersegment Elimination [Member]
Segment Reporting Information [Line Items]
Revenue		(6.1)	(6.5)
Intersegment Elimination [Member] | Entertainment and Communications [Member]
Segment Reporting Information [Line Items]
Revenue		5.2	5.4
Intersegment Elimination [Member] | IT Services and Hardware [Member]
Segment Reporting Information [Line Items]
Revenue		0.9	1.1
Intersegment Elimination [Member] | Corporate Segment [Member]
Segment Reporting Information [Line Items]
Assets		589.1		$ 593.5
Sales [Member] | Intersegment Elimination [Member]
Segment Reporting Information [Line Items]
Revenue		6.1	6.5
Expenditures for Long-Lived Assets, Including Acquisitions of Businesses [Member]
Segment Reporting Information [Line Items]
Expenditures for long-lived assets	[1]	35.5	64.3
Expenditures for Long-Lived Assets, Including Acquisitions of Businesses [Member] | IT Services and Hardware [Member]
Segment Reporting Information [Line Items]
Expenditures for long-lived assets	[1]	$ 7.9	$ 17.5

[1] Includes cost of acquisitions