Property and Equipment - Property and Equipment (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property and equipment excluding land gross	$ 258,900	$ 243,000
Less accumulated depreciation	188,579	187,375
Property and equipment excluding land, net	70,300	55,600
Land	9,300	9,300
Property and equipment, total	79,642	64,939
Buildings
Property, Plant and Equipment [Line Items]
Property and equipment excluding land gross	$ 21,900	21,800
Property and equipment, Estimated useful life	40 years
Construction in progress
Property, Plant and Equipment [Line Items]
Property and equipment excluding land gross	$ 15,100	10,000
Transmission, studio and other broadcast equipment
Property, Plant and Equipment [Line Items]
Property and equipment excluding land gross	$ 162,100	151,300
Transmission, studio and other broadcast equipment | Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, Estimated useful life	5 years
Transmission, studio and other broadcast equipment | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, Estimated useful life	15 years
Office and computer equipment
Property, Plant and Equipment [Line Items]
Property and equipment excluding land gross	$ 31,400	30,600
Office and computer equipment | Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, Estimated useful life	3 years
Office and computer equipment | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, Estimated useful life	7 years
Transportation equipment
Property, Plant and Equipment [Line Items]
Property and equipment excluding land gross	$ 6,300	6,300
Property and equipment, Estimated useful life	5 years
Leasehold improvements and land improvements
Property, Plant and Equipment [Line Items]
Property and equipment excluding land gross	$ 22,100	$ 23,000
Property and equipment, Estimated useful life	Lesser of lease life or useful life