Impairment of Goodwill and Other Indefinite-Lived Intangible Assets - Fair Value Measurement Inputs and Valuation Techniques (Detail)

v3.10.0.1

Impairment of Goodwill and Other Indefinite-Lived Intangible Assets - Fair Value Measurement Inputs and Valuation Techniques (Detail) - Broadcast Licenses [Member]	Sep. 30, 2018
Measurement Input, Long-term Revenue Growth Rate [Member]
Goodwill And Other Intangible Assets [Line Items]
Derivative asset measurement input percentage	1.9
Measurement Input, Risk-adjusted Discount Rate [Member]
Goodwill And Other Intangible Assets [Line Items]
Derivative asset measurement input percentage	9.0
Minimum [Member] | Measurement Input, Operating Profit Margin [Member]
Goodwill And Other Intangible Assets [Line Items]
Derivative asset measurement input percentage	(13.9)
Maximum [Member] | Measurement Input, Operating Profit Margin [Member]
Goodwill And Other Intangible Assets [Line Items]
Derivative asset measurement input percentage	30.8