Broadcast Licenses, Goodwill and Other Intangible Assets (Details Textual) - USD ($)	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
Finite-Lived Intangible Assets [Line Items]
Impairment of intangible assets	$ 0	$ 0	$ 0	$ 0	$ 1,449,000	$ 0	$ 0	$ 0		$ 0	$ 1,449,000	$ 0
Amortization Expense										1,094,000	$ 860,000	$ 642,000
2019	1,029,000									1,029,000
2020	813,000									813,000
2021	387,000									387,000
2022	39,000									39,000
2023	$ 35,000									$ 35,000

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