Property and Equipment and Intangible Assets - Estimated Future Amortization (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Intangible Assets
Intangible Assets	$ 139,769	$ 139,769
Accumulated Amortization	(122,314)	(112,615)
Amortization expense	10,000	8,000	$ 10,000
Goodwill	126,000
Estimated future amortization of identifiable intangible assets
2019	7,402
2020	3,816
2021	1,288
2022	666
2023	654
Thereafter	3,629
Total	17,455
Wireless
Intangible Assets
Goodwill	$ 126,000	126,000
Minimum
Intangible Assets
Useful life	5 years
Maximum
Intangible Assets
Useful life	20 years
Technology-based
Intangible Assets
Intangible Assets	$ 63,077	63,077
Accumulated Amortization	(53,998)	(48,416)
Trademarks
Intangible Assets
Intangible Assets	37,010	37,010
Accumulated Amortization	(28,634)	(24,517)
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)