Summary of Significant Accounting Policies (Narrative) (Details)									1 Months Ended		12 Months Ended
	Mar. 04, 2020 USD ($) $ / shares	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	Nov. 28, 2018 USD ($) $ / shares	Feb. 28, 2018 USD ($) $ / shares	Dec. 31, 2020 USD ($) segment $ / shares shares	Dec. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2020 USD ($)	Dec. 31, 2020	Dec. 31, 2020 item	Mar. 31, 2013 USD ($)	Feb. 28, 2013 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Number Of FM Radio Stations											79
Number Of AM Radio Stations											34
Number Of Metro Signals											78
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount | shares											0	0	0
Number of Reportable Segments | segment											1
Concentration Risk, Market Risk											39.00%	39.00%	41.00%
Time deposits												$ 0	$ 0	$ 0
Interest expense related to the amortization of debt issuance costs											$ 40,000	103,000	51,000
Write-off of debt issuance costs											$ 40,000	103,000	$ 51,000
Net book value of deferred costs												$ 104,000		64,000
Treasury Stock, Shares, Acquired | shares											24,255	39,505	53,713
Treasury Stock Acquired, Average Cost Per Share | $ / shares											$ 18.51	$ 29.68	$ 37.24
Cash dividend paid | $ / shares									$ 0.30
Dividend paid	$ 1,900,000	$ 1,800,000	$ 1,800,000	$ 1,800,000		$ 1,800,000	$ 1,800,000	$ 1,800,000	$ 3,300,000	$ 1,800,000
Number Of Broadcast Licenses															114
Number Of Market Serving															27	27
Debt Issuance Costs, Net													$ 120,000
Operating Lease, Right-of-Use Asset												$ 6,900,000		6,600,000
Operating Lease, Liability, Statement of Financial Position [Extensible List]											Other Liabilities, Noncurrent	Other Liabilities, Noncurrent
Operating Lease, Liability												$ 7,000,000.0		6,949,000
Number of operating segments | segment											1
Customer relationships [Member]
Summary Of Significant Accounting Policies [Line Items]
Finite-Lived Intangible Asset, Useful Life											3 years
Continuing Operations [Member]
Summary Of Significant Accounting Policies [Line Items]
Depreciation expense											$ 5,711,000	5,916,000	5,692,000
Advertising and promotion costs											$ 985,000	$ 2,442,000	$ 2,438,000
Class A Common Stock
Summary Of Significant Accounting Policies [Line Items]
Stock Repurchase Program, Remaining Authorized Repurchase Amount														$ 18,800,000
Common Class A and Common Class B
Summary Of Significant Accounting Policies [Line Items]
Cash dividend paid | $ / shares	$ 0.32	$ 0.30	$ 0.30		$ 0.30	$ 0.30	$ 0.30	$ 0.30	$ 0.25	$ 0.30
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