Property and Equipment and Intangible Assets - Estimated Future Amortization (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Intangible Assets
Intangible Assets	$ 139,769	$ 148,456
Accumulated Amortization	(112,615)	(115,730)
Amortization expense	8,000	10,000	$ 13,000
Goodwill	126,000	126,000
Estimated future amortization of identifiable intangible assets
2018	9,698
2019	7,402
2020	3,816
2021	1,288
2022	666
Thereafter	4,284
Total	27,154
Wireless
Intangible Assets
Goodwill	$ 126,000
Minimum
Intangible Assets
Useful life	1 year
Maximum
Intangible Assets
Useful life	20 years
Technology-based
Intangible Assets
Intangible Assets	$ 63,077	60,634
Accumulated Amortization	(48,416)	(44,331)
Trademarks
Intangible Assets
Intangible Assets	37,010	48,140
Accumulated Amortization	(24,517)	(31,717)
Contract-based
Intangible Assets
Intangible Assets	13,149	13,149
Accumulated Amortization	(13,149)	(13,149)
Customer relationships
Intangible Assets
Intangible Assets	26,533	26,533
Accumulated Amortization	$ (26,533)	$ (26,533)