Goodwill and Other Intangible Assets - Composition of Company's Acquired Intangible Assets and Associated Accumulated Amortization (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Schedule Of Intangible Assets [Line Items]
Gross Carrying Amount	$ 116,391	$ 114,390
Accumulated Amortization	93,793	87,632
Net Carrying Amount	22,598	26,758
Intangible assets not subject to amortization:
Total intangible assets	277,196	277,921
FCC Licenses and Spectrum Usage Rights
Intangible assets not subject to amortization:
Licenses	$ 254,598	251,163
Television network affiliation agreements
Schedule Of Intangible Assets [Line Items]
Weighted average remaining life in years	8 years
Gross Carrying Amount	$ 67,489	67,489
Accumulated Amortization	56,950	55,560
Net Carrying Amount	$ 10,539	11,929
Customer base
Schedule Of Intangible Assets [Line Items]
Weighted average remaining life in years	5 years
Gross Carrying Amount	$ 10,045	9,146
Accumulated Amortization	5,044	3,839
Net Carrying Amount	$ 5,001	5,307
Pre-sold advertising contracts and other
Schedule Of Intangible Assets [Line Items]
Weighted average remaining life in years	6 years
Gross Carrying Amount	$ 38,857	37,755
Accumulated Amortization	31,799	28,233
Net Carrying Amount	$ 7,058	$ 9,522