Property and Equipment - Property and Equipment (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Property and equipment excluding land gross	$ 251,500	$ 248,000
Less accumulated depreciation	204,343	198,282
Property and equipment excluding land, net	47,200	49,700
Land	8,200	8,200
Property and equipment, total	55,368	57,874
Buildings
Property, Plant and Equipment [Line Items]
Property and equipment excluding land gross	$ 18,600	18,600
Property and equipment, Estimated useful life	39 years
Construction in progress
Property, Plant and Equipment [Line Items]
Property and equipment excluding land gross	$ 2,600	2,900
Transmission, studio and other broadcast equipment
Property, Plant and Equipment [Line Items]
Property and equipment excluding land gross	$ 166,900	163,300
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	$ 30,200	29,600
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	$ 6,800	6,700
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	$ 26,400	$ 26,900
Property and equipment, Estimated useful life	Lesser of lease life or useful life