Summary of Significant Accounting Policies - Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended			18 Months Ended
	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2015	Jul. 02, 2014
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 31,343	$ 31,343	$ 36,747	$ 40,454	$ 36,747
Service revenue since acquisition					$ 55,100
Depreciation		7,608	7,193	6,127
Amortization of Intangible Assets		4,956	$ 5,526	$ 3,859
Videotel
Finite-Lived Intangible Assets [Line Items]
Goodwill						$ 23,151
Business Combination, Contingent Consideration, Liability						$ 47,446
Service revenue since acquisition		21,500
Exceeds carrying value by less than 10% [Member]
Finite-Lived Intangible Assets [Line Items]
Goodwill	4,401	$ 4,401
Service Life [Member]
Finite-Lived Intangible Assets [Line Items]
Depreciation	368
Amortization of Intangible Assets	$ 188