Summary of Significant Accounting Policies (Details Texual) $ / shares in Units, $ in Thousands				1 Months Ended		3 Months Ended
	Dec. 11, 2019 $ / shares	Sep. 12, 2019 $ / shares	Mar. 04, 2019 $ / shares	May 30, 2019 $ / shares	Feb. 26, 2019 $ / shares	Mar. 31, 2020 USD ($) item $ / shares shares	Mar. 31, 2019 USD ($) $ / shares shares
Summary Of Significant Accounting Policies [Line Items]
Number Of FM Radio Stations | item						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
Special cash dividend declared on Classes A and B Common Stock | $ / shares						$ 0.32	$ 0.30
Number Of Market Serving | item						27
Stock Repurchase Program, Remaining Authorized Repurchase Amount						$ 19,200
Stock Repurchase Program, Authorized Amount						75,800
Operating Lease, Right-of-Use Asset						6,800	$ 6,300
Operating Lease, Liability						$ 7,015	$ 6,400
Customer relationships [Member]
Summary Of Significant Accounting Policies [Line Items]
Finite-Lived Intangible Asset, Useful Life						3 years
Class A Common Stock
Summary Of Significant Accounting Policies [Line Items]
Special cash dividend declared on Classes A and B Common Stock | $ / shares	$ 0.30	$ 0.30	$ 0.32	$ 0.30	$ 0.30