Goodwill and Intangible Assets Goodwill (Details) - USD ($)		12 Months Ended
	Oct. 02, 2017	Dec. 31, 2017	Dec. 31, 2016
Goodwill [Roll Forward]
Goodwill, Beginning Balance		$ 14,300,000	$ 14,300,000
Goodwill, Acquisitions		137,000,000	0
Goodwill, Currency Translations		(300,000)	0
Goodwill, Ending Balance		151,000,000	14,300,000
Goodwill, Impairment Loss		0	0
Impairment of Intangible Assets, Finite-lived		0	0
IT Services and Hardware [Member]
Goodwill [Roll Forward]
Goodwill, Beginning Balance		2,400,000	2,400,000
Goodwill, Acquisitions		137,000,000	0
Goodwill, Currency Translations		(300,000)	0
Goodwill, Ending Balance		139,100,000	2,400,000
Entertainment and Communications [Member]
Goodwill [Roll Forward]
Goodwill, Beginning Balance		11,900,000	11,900,000
Goodwill, Acquisitions		0	0
Goodwill, Currency Translations		0	0
Goodwill, Ending Balance		11,900,000	$ 11,900,000
SunTel Services [Member] | IT Services and Hardware [Member]
Goodwill [Roll Forward]
Goodwill, Acquisitions		4,600,000
OnX Holdings LLC [Member]
Goodwill [Roll Forward]
Goodwill, Ending Balance	$ 132,400,000
OnX Holdings LLC [Member] | IT Services and Hardware [Member]
Goodwill [Roll Forward]
Goodwill, Acquisitions		$ 132,400,000
OnX Holdings LLC [Member] | Customer Relationships [Member]
Goodwill [Roll Forward]
Finite-Lived Intangible Asset, Useful Life	15 years
Minimum [Member] | Customer Relationships [Member]
Goodwill [Roll Forward]
Finite-Lived Intangible Asset, Useful Life		8 years
Maximum [Member] | Customer Relationships [Member]
Goodwill [Roll Forward]
Finite-Lived Intangible Asset, Useful Life		15 years