Revenue (Details) - USD ($) $ in Thousands	3 Months Ended									12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	[1]	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues [Abstract]
Revenue, Net, Total	$ 32,938	$ 31,648	$ 32,234	$ 28,009	$ 31,464	$ 30,269	$ 30,261	$ 26,155		$ 124,829	$ 118,149	$ 118,955
Broadcast Advertising Revenue, net [Member]
Revenues [Abstract]
Revenue, Net, Total										114,929	109,175	110,053
Digital Advertising Revenue [Member]
Revenues [Abstract]
Revenue, Net, Total										3,900	3,610	3,567
Other Revenue [Member]
Revenues [Abstract]
Revenue, Net, Total										$ 6,000	$ 5,364	$ 5,335

[1] March 31, 2017 quarterly data have been reclassified to conform with current presentation.