Business Combination - Acquisition Details (Details) - USD ($) $ in Thousands	Jan. 01, 2016	Dec. 31, 2015	Dec. 31, 2017
Business Acquisition [Line Items]
Ownership percentage sold	1.00%
Proceeds from sale of variable interest entity	$ 500
ALLO Communications [Member]
Business Acquisition [Line Items]
Percentage of voting interests acquired		92.50%
Consideration transferred		$ 46,250
Noncontrolling interest, ownership percentage			7.50%
Noncontrolling Interest, minimum earn up percentage by noncontrolling owners			11.50%
Maximum earn up percentage by noncontrolling owners			19.00%
Acquired intangible assets		$ 11,410
Acquired intangible asset useful life		12 years
Expected tax deductible goodwill		$ 21,100
Customer Relationships [Member] | ALLO Communications [Member]
Business Acquisition [Line Items]
Acquired intangible asset useful life		10 years
Finite-lived intangible assets acquired		$ 6,300
Trade Names [Member] | ALLO Communications [Member]
Business Acquisition [Line Items]
Acquired intangible asset useful life		15 years
Finite-lived intangible assets acquired		$ 5,100
ALLO Communications [Member]
Business Acquisition [Line Items]
Compensation expense to be recognized over performance period			$ 1,000