Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accounting Policies [Line Items]
Estimated losses for bad debts									$ 400,000	$ (200,000)	$ 1,000,000
Bad debts actually charged off									900,000	1,100,000	700,000
Long term debt fair value	340,300,000				364,100,000				340,300,000	364,100,000
Percentage of tax benefit recognized									50.00%
Advertising expense									500,000	300,000	300,000
Period to grant television station for terms of retransmission consent agreements									6 years
Retransmission consent agreements expiring date									Dec. 31, 2014
Retransmission consent revenue									26,400,000	22,200,000	20,200,000
Net revenue	65,262,000	62,274,000	61,846,000	52,656,000	60,093,000	57,786,000	56,950,000	49,087,000	242,038,000	223,916,000	223,253,000
Broadcast trade cost									500,000	500,000	600,000
Shares of dilutive securities not included in computation of diluted income per share									1,116,750	5,670,908	8,573,761
Comprehensive income (loss)									(2,372,000)	234,000	0
Broadcast Equipment
Accounting Policies [Line Items]
Net revenue									$ 500,000	$ 500,000	$ 600,000
Interest Rate Swap Agreements
Accounting Policies [Line Items]
Term loan beginning date									Dec. 31, 2015