Goodwill - Summary of Key Assumptions Used in the Discounted Cash Flow Analyses (Detail)	3 Months Ended				12 Months Ended
	Dec. 31, 2023	Sep. 30, 2023	Dec. 31, 2022	Jun. 30, 2022	Dec. 31, 2023
Minimum [Member]
Disclosure in tabular form of assumptions used in determination of fair value of goodwill [Line Items]
Operating income margins	19.70%	19.70%	19.70%	19.20%
Maximum [Member]
Disclosure in tabular form of assumptions used in determination of fair value of goodwill [Line Items]
Operating income margins	29.90%	30.40%	30.40%	32.60%
Measurement Input, Long-term Revenue Growth Rate [Member] | Minimum [Member]
Disclosure in tabular form of assumptions used in determination of fair value of goodwill [Line Items]
Revenue growth rates	(16.50%)	(1.20%)	0.30%	(1.90%)
Measurement Input, Long-term Revenue Growth Rate [Member] | Maximum [Member]
Disclosure in tabular form of assumptions used in determination of fair value of goodwill [Line Items]
Revenue growth rates	24.40%	1.80%	2.70%	15.90%
Measurement Input, Discount Rate [Member]
Disclosure in tabular form of assumptions used in determination of fair value of goodwill [Line Items]
Revenue growth rates	10.00%	10.00%	9.50%	9.50%
Goodwill [Member] | Minimum [Member]
Disclosure in tabular form of assumptions used in determination of fair value of goodwill [Line Items]
Operating income margins					5.40%
Goodwill [Member] | Maximum [Member]
Disclosure in tabular form of assumptions used in determination of fair value of goodwill [Line Items]
Operating income margins					29.80%
Goodwill [Member] | Measurement Input, Long-term Revenue Growth Rate [Member] | Minimum [Member]
Disclosure in tabular form of assumptions used in determination of fair value of goodwill [Line Items]
Revenue growth rates					(1.90%)
Goodwill [Member] | Measurement Input, Long-term Revenue Growth Rate [Member] | Maximum [Member]
Disclosure in tabular form of assumptions used in determination of fair value of goodwill [Line Items]
Revenue growth rates					11.10%
Goodwill [Member] | Measurement Input, Discount Rate [Member]
Disclosure in tabular form of assumptions used in determination of fair value of goodwill [Line Items]
Revenue growth rates					9.50%
Boston, MA radio market cluster [Member] | Goodwill [Member]
Disclosure in tabular form of assumptions used in determination of fair value of goodwill [Line Items]
Operating income margins					13.10%
Boston, MA radio market cluster [Member] | Goodwill [Member] | Measurement Input, Long-term Revenue Growth Rate [Member] | Minimum [Member]
Disclosure in tabular form of assumptions used in determination of fair value of goodwill [Line Items]
Revenue growth rates					0.50%
Boston, MA radio market cluster [Member] | Goodwill [Member] | Measurement Input, Long-term Revenue Growth Rate [Member] | Maximum [Member]
Disclosure in tabular form of assumptions used in determination of fair value of goodwill [Line Items]
Revenue growth rates					11.40%
Boston, MA radio market cluster [Member] | Goodwill [Member] | Measurement Input, Discount Rate [Member]
Disclosure in tabular form of assumptions used in determination of fair value of goodwill [Line Items]
Revenue growth rates					9.50%
Philadelphia, PA market cluster [Member] | Goodwill [Member]
Disclosure in tabular form of assumptions used in determination of fair value of goodwill [Line Items]
Operating income margins					27.90%
Philadelphia, PA market cluster [Member] | Goodwill [Member] | Measurement Input, Long-term Revenue Growth Rate [Member] | Minimum [Member]
Disclosure in tabular form of assumptions used in determination of fair value of goodwill [Line Items]
Revenue growth rates					(9.30%)
Philadelphia, PA market cluster [Member] | Goodwill [Member] | Measurement Input, Long-term Revenue Growth Rate [Member] | Maximum [Member]
Disclosure in tabular form of assumptions used in determination of fair value of goodwill [Line Items]
Revenue growth rates					1.40%
Philadelphia, PA market cluster [Member] | Goodwill [Member] | Measurement Input, Discount Rate [Member]
Disclosure in tabular form of assumptions used in determination of fair value of goodwill [Line Items]
Revenue growth rates					10.00%