Summary of Significant Accounting Policies (Details Textual)												1 Months Ended		12 Months Ended
	Dec. 11, 2019 USD ($) $ / shares	Sep. 12, 2019 USD ($) $ / shares	Jul. 05, 2019 USD ($)	May 30, 2019 $ / shares	Feb. 26, 2019 USD ($) $ / shares	Sep. 14, 2018 USD ($) $ / shares	May 15, 2018 USD ($) $ / shares	Dec. 07, 2017 USD ($) $ / shares	Sep. 13, 2017 USD ($) $ / shares	May 03, 2017 USD ($) $ / shares	Mar. 03, 2017 USD ($) $ / shares	Nov. 28, 2018 USD ($) $ / shares	Feb. 28, 2018 USD ($) $ / shares	Dec. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2017 USD ($) $ / shares shares	Jan. 01, 2019 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Number Of FM Radio Stations														79
Number Of AM Radio Stations														34
Number Of Metro Signals														77
Number of Reportable Segments														1	1	1
Concentration Risk, Market Risk														39.00%	41.00%	41.00%
Interest expense related to the amortization of debt issuance costs														$ 103,000	$ 51,000	$ 53,000
Write-off of debt issuance costs														103,000	51,000	$ 53,000
Net book value of deferred costs														$ 104,000	$ 207,000
Treasury Stock, Shares, Acquired | shares														39,505	53,713	37,141
Treasury Stock Acquired, Average Cost Per Share | $ / shares														$ 29.68	$ 37.24	$ 47.72
Special cash dividend declared on Classes A and B Common Stock | $ / shares	$ 0.30	$ 0.30		$ 0.30	$ 0.30	$ 0.30	$ 0.30	$ 0.30	$ 0.30	$ 0.30	$ 0.30	$ 0.30	$ 0.30	$ 1.20	$ 1.45	$ 2.00
Dividend paid	$ 1,800,000	$ 1,800,000	$ 1,800,000		$ 1,800,000	$ 1,800,000	$ 1,800,000	$ 6,500,000	$ 1,800,000	$ 1,800,000	$ 1,800,000	$ 3,300,000	$ 1,800,000
Number Of Broadcast Licenses														113
Number Of Market Serving														27
Dividends Payable, Amount Per Share | $ / shares								$ 0.80				$ 0.25
Debt Issuance Costs, Net														$ 120,000	$ 120,000
Operating Lease, Right-of-Use Asset														$ 6,900,000
Operating Lease, Liability, Statement of Financial Position [Extensible List]														Operating Lease, Liability
Operating Lease, Liability														$ 6,997,000
Customer relationships [Member]
Summary Of Significant Accounting Policies [Line Items]
Finite-Lived Intangible Asset, Useful Life														3 years
Accounting Standards Update 2016-02 [Member]
Summary Of Significant Accounting Policies [Line Items]
Operating Lease, Right-of-Use Asset																	$ 6,700,000
Operating Lease, Liability																	$ 6,700,000
Continuing Operations [Member]
Summary Of Significant Accounting Policies [Line Items]
Depreciation expense														$ 5,916,000	5,692,000	$ 5,391,000
Advertising and promotion costs														2,442,000	2,438,000	2,441,000
Discontinued Operations [Member]
Summary Of Significant Accounting Policies [Line Items]
Depreciation expense														0	0	445,000
Advertising and promotion costs														0	$ 0	$ 240,000
Class A Common Stock
Summary Of Significant Accounting Policies [Line Items]
Stock Repurchase Program, Remaining Authorized Repurchase Amount														$ 19,200,000
Minimum [Member] | Lease Agreements [Member]
Summary Of Significant Accounting Policies [Line Items]
Finite-Lived Intangible Asset, Useful Life														1 year
Minimum [Member] | Other intangibles [Member]
Summary Of Significant Accounting Policies [Line Items]
Finite-Lived Intangible Asset, Useful Life														1 year
Minimum [Member] | Class A Common Stock
Summary Of Significant Accounting Policies [Line Items]
Stock Repurchase Program, Authorized Amount														$ 60,000,000
Maximum [Member] | Lease Agreements [Member]
Summary Of Significant Accounting Policies [Line Items]
Finite-Lived Intangible Asset, Useful Life														26 years
Maximum [Member] | Other intangibles [Member]
Summary Of Significant Accounting Policies [Line Items]
Finite-Lived Intangible Asset, Useful Life														15 years
Maximum [Member] | Class A Common Stock
Summary Of Significant Accounting Policies [Line Items]
Stock Repurchase Program, Authorized Amount														$ 75,800,000