Summary of Significant Accounting Policies (Details 1) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property Plant and Equipment, Gross	$ 135,856	$ 134,680
Accumulated depreciation	(79,621)	(85,506)
Net property and equipment	56,235	49,174
Land and Land Improvements [Member]
Property, Plant and Equipment [Line Items]
Property Plant and Equipment, Gross	$ 13,594	12,307
Estimated Useful Life	0 years
Building [Member]
Property, Plant and Equipment [Line Items]
Property Plant and Equipment, Gross	$ 34,905	32,046
Estimated Useful Life	31 years 6 months
Towers And Antennae [Member]
Property, Plant and Equipment [Line Items]
Property Plant and Equipment, Gross	$ 24,538	23,066
Towers And Antennae [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	7 years
Towers And Antennae [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	15 years
Equipment [Member]
Property, Plant and Equipment [Line Items]
Property Plant and Equipment, Gross	$ 52,534	56,745
Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	3 years
Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	15 years
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property Plant and Equipment, Gross	$ 6,822	7,261
Furniture and Fixtures [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	7 years
Furniture and Fixtures [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated Useful Life	20 years
Vehicles [Member]
Property, Plant and Equipment [Line Items]
Property Plant and Equipment, Gross	$ 3,463	$ 3,255
Estimated Useful Life	5 years