Summary of Significant Accounting Policies (Narrative) (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2021 USD ($) item shares	Jun. 30, 2020 shares	Jun. 30, 2021 USD ($) item segment shares	Jun. 30, 2020 shares	Dec. 31, 2020 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Number Of FM Radio Stations | item			79
Number Of AM Radio Stations			35
Number Of Metro Signals			79
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount | shares	0	0	0	0
Number of Reportable Segments | item			27
Number Of Market Serving | item	27		27
Operating Lease, Right-of-Use Asset | $	$ 5,900,000		$ 5,900,000		$ 6,600,000
Operating Lease, Liability | $	6,248,000		$ 6,248,000		6,900,000
Number of operating segments | segment			1
Allowance for doubtful accounts receivable | $	$ 446,000		$ 446,000		$ 648,000
Customer relationships [Member]
Summary Of Significant Accounting Policies [Line Items]
Finite-Lived Intangible Asset, Useful Life			3 years