Quarterly Results of Operations (Details) - USD ($) $ / shares in Units, shares in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Quarterly Results of Operations (Unaudited)
Net operating revenue	$ 28,753,000	$ 24,143,000	$ 16,866,000	$ 26,051,000	$ 31,791,000	$ 31,274,000	$ 32,191,000	$ 27,816,000	$ 95,813,000	$ 123,072,000	$ 124,829,000
Station operating expenses	21,119,000	19,616,000	18,652,000	22,199,000	23,050,000	23,600,000	22,879,000	23,163,000	81,586,000	92,692,000	93,727,000
Corporate G&A	2,651,000	2,838,000	3,070,000	3,015,000	3,281,000	2,788,000	2,706,000	2,685,000	11,574,000	11,460,000	11,359,000
Other operating expense (income), net	(13,000)	50,000	46,000	(1,330,000)	26,000	85,000	(2,000)	3,000	(1,247,000)	112,000	61,000
Impairment of intangible assets, broadcast licenses		1,392,000	3,757,000						5,149,000	0	0
Operating income	4,996,000	247,000	(8,659,000)	2,167,000	5,434,000	4,801,000	6,608,000	1,965,000	(1,249,000)	18,808,000	19,682,000
Other (income) expenses:
Interest expense	75,000	75,000	82,000	108,000	163,000	180,000	184,000	208,000	340,000	735,000	946,000
Interest income	(7,000)	(8,000)	(25,000)	(108,000)	(125,000)	(162,000)	(160,000)	(163,000)	(148,000)	(610,000)	(631,000)
Other (income) expenses	(20,000)			(213,000)	(5,000)	(11,000)			(233,000)	(16,000)	(23,000)
Income before income taxes	4,948,000	180,000	(8,716,000)	2,380,000	5,401,000	4,794,000	6,584,000	1,920,000	(1,208,000)	18,699,000	19,390,000
Income tax provision	2,680,000	1,130,000	(3,805,000)	700,000	1,560,000	1,460,000	1,850,000	550,000	$ 705,000	$ 5,420,000	$ 5,700,000
Net income	$ 2,268,000	$ (950,000)	$ (4,911,000)	$ 1,680,000	$ 3,841,000	$ 3,334,000	$ 4,734,000	$ 1,370,000
Basic	$ 0.38	$ (0.16)	$ (0.82)	$ 0.28	$ 0.64	$ 0.56	$ 0.80	$ 0.23	$ (0.32)	$ 2.23	$ 2.30
Weighted average common shares	5,880	5,869	5,868	5,866	5,817	5,834	5,844	5,841	5,871	5,834	5,829
Diluted earnings per share	$ 0.38	$ (0.16)	$ (0.82)	$ 0.28	$ 0.64	$ 0.56	$ 0.80	$ 0.23	$ (0.32)	$ 2.23	$ 2.30
Weighted average common and common equivalent shares	5,880	5,869	5,868	5,866	5,817	5,834	5,844	5,841	5,871	5,834	5,829