Quarterly Results of Operations (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Results of Operations (Unaudited)
Net operating revenue	$ 31,791	$ 31,274	$ 32,191	$ 27,816	$ 32,938	$ 31,648	$ 32,234	$ 28,009	$ 123,072	$ 124,829	$ 118,149
Station operating expense	23,050	23,600	22,879	23,163	23,761	23,429	23,140	23,397	92,692	93,727	87,759
Corporate G&A	3,281	2,788	2,706	2,685	3,154	2,813	2,848	2,544	11,460	11,359	11,657
Other operating expense (income), net	26	85	(2)	3	14	85	213	(251)	112	61	55
Operating income	5,434	4,801	6,608	1,965	6,009	5,321	6,033	2,319	18,808	19,682	17,229
Other (income) expenses:
Interest expense	163	180	184	208	229	243	255	219	735	946	903
Interest income	(125)	(162)	(160)	(163)	(187)	(167)	(188)	(89)	(610)	(631)	0
Other (income) expenses	(5)	(11)	0	0	2	(25)	0	0
Income before income taxes	5,401	4,794	6,584	1,920	5,965	5,270	5,966	2,189	18,699	19,390	16,326
Income tax provision	1,560	1,460	1,850	550	1,670	1,575	1,795	660	5,420	5,700	(5,920)
Net income	$ 3,841	$ 3,334	$ 4,734	$ 1,370	$ 4,295	$ 3,695	$ 4,171	$ 1,529	$ 13,279	$ 13,690	$ 22,246
Basic earnings per share	$ 0.64	$ 0.56	$ 0.80	$ 0.23	$ 0.72	$ 0.62	$ 0.70	$ 0.26	$ 2.23	$ 2.30	$ 9.27
Weighted average common shares	5,817	5,834	5,844	5,841	5,820	5,822	5,834	5,842	5,834	5,829	5,803
Diluted earnings per share	$ 0.64	$ 0.56	$ 0.80	$ 0.23	$ 0.72	$ 0.62	$ 0.70	$ 0.26	$ 2.23	$ 2.30	$ 9.27
Weighted average common and common equivalent shares	5,817	5,834	5,844	5,841	5,820	5,822	5,834	5,842	5,834	5,829	5,807