Goodwill and Other Intangible Assets - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014 Segment	Dec. 31, 2013	Dec. 31, 2012
Goodwill [Line Items]
Aggregate amortization expense	$ 3,000,000	$ 2,500,000	$ 2,700,000
Number of reporting segments	3
Impairment of goodwill	735,000
Radio
Goodwill [Line Items]
Impairment of goodwill	735,000	0
Television
Goodwill [Line Items]
Impairment of goodwill	$ 0	$ 0