Goodwill and Other Intangible Assets - Carrying Amount of Goodwill (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Goodwill [Line Items]
Goodwill, Beginning balance	$ 70,729,000	$ 50,081,000
Acquisition	3,563,000	20,648,000
Goodwill, Ending balance	74,292,000	70,729,000
Television
Goodwill [Line Items]
Goodwill, Beginning balance	40,549,000	35,912,000
Acquisition		4,637,000
Impairment	0
Goodwill, Ending balance	40,549,000	40,549,000
Radio
Goodwill [Line Items]
Goodwill, Beginning balance	0
Goodwill, Ending balance	0	0
Digital Media
Goodwill [Line Items]
Goodwill, Beginning balance	30,180,000	14,169,000
Acquisition	3,563,000	16,011,000
Impairment	0
Goodwill, Ending balance	$ 33,743,000	$ 30,180,000