The Company and Significant Accounting Policies - Additional Information (Detail)				3 Months Ended			9 Months Ended		13 Months Ended
	Dec. 30, 2014 USD ($)	Nov. 25, 2014 USD ($)	Dec. 31, 2013 USD ($)	Sep. 30, 2015 USD ($) shares	Sep. 30, 2014 USD ($) shares	Sep. 30, 2013 USD ($)	Sep. 30, 2015 USD ($) shares	Sep. 30, 2014 USD ($) shares	Sep. 30, 2015 USD ($) $ / shares shares	Dec. 31, 2014 USD ($)	Aug. 18, 2014 USD ($)	Dec. 16, 2013 USD ($) Derivative	May. 31, 2013 USD ($)
Accounting Policies [Line Items]
Non-cash stock-based compensation				$ 900,000	$ 900,000		$ 2,684,000	$ 2,192,000
Total unrecognized compensation expense employee stock option plans				$ 1,100,000			$ 1,100,000		$ 1,100,000
Shares of dilutive securities not included in computation of diluted income per share | shares				10,211	1,274,750		50,806	1,336,750
Interest Rate Swap Agreements
Accounting Policies [Line Items]
Interest rate swap inception date							Dec. 16, 2013
Number of forward-starting swap agreements | Derivative												3
Aggregated notional amount of interest swap agreements												$ 186,000,000
Derivative average Interest rate												2.73%
Derivative fixed Interest rate												5.23%
Interest rate swap effective date							Dec. 31, 2015
Interest rate swap expiration date							Dec. 31, 2018
Change in fair value of interest rate				$ (1,100,000)	$ 500,000		$ (2,300,000)	$ (1,300,000)
Unrealized gains or losses included in accumulated other comprehensive income or loss							0
Fair value of the interest rate swap liability				$ 7,200,000			$ 7,200,000		$ 7,200,000	$ 3,400,000
Term Loan B Facility
Accounting Policies [Line Items]
Gain (loss) on debt extinguishment						$ (29,700,000)
Repayment of loans	$ 20,000,000		$ 10,000,000
Two Thousand Thirteen Revolving Credit Facility
Accounting Policies [Line Items]
Effective interest rate				3.50%			3.50%		3.50%
Interest rate on borrowings under 2013 Credit Facility							if a Base Rate Loan, one and one half percent (1.50%) per annum and (B) if a LIBOR Rate Loan, two and one half percent (2.50%) per annum;
Percentage of repricing fee							1.00%
Certain customary events of default, number of business days to default in the payment of interest on borrowings							3 days
Certain customary events of default, number of days default continue for compliance with other agreement							30 days
Certain customary events of default, number of days default continue for financial statement delivery obligations							10 days
Certain customary events of default, indebtedness aggregate amount							$ 15,000,000
Certain customary events of default, failure in payment of final judgments aggregate amount							$ 15,000,000
Certain customary events of default, failure in payment of final judgments aggregate amount period							30 days
Two Thousand Thirteen Revolving Credit Facility | Base Rate Margin
Accounting Policies [Line Items]
Variable interest rate basis spread on debt							1.50%
Two Thousand Thirteen Revolving Credit Facility | LIBOR Margin
Accounting Policies [Line Items]
Variable interest rate basis spread on debt							2.50%
Two Thousand Thirteen Revolving Credit Facility | Term Loan B Facility
Accounting Policies [Line Items]
Senior Secured debt													$ 375,000,000
Maturity date of revolving credit facility							May 31, 2020
Period considered for applicability of repricing fees							6 months
Principal amount repurchased			$ 324,000,000
Redemption price on principal amount with net proceeds, accrued and unpaid expenses			106.563%
Carrying value of term loan				$ 337,500,000			$ 337,500,000		$ 337,500,000
Estimated fair value of term loan				$ 337,500,000			$ 337,500,000		$ 337,500,000
Two Thousand Thirteen Revolving Credit Facility | Senior Secured Revolving Credit Facility
Accounting Policies [Line Items]
Senior Secured debt													30,000,000
Maturity date of revolving credit facility							May 31, 2018
Two Thousand Thirteen Revolving Credit Facility | Term Loan A
Accounting Policies [Line Items]
Senior Secured debt													20,000,000
Maturity date of revolving credit facility							Aug. 01, 2013
Two Thousand Thirteen Revolving Credit Facility | Term Loan And Revolving Credit Facility
Accounting Policies [Line Items]
Additional borrowing capacity													$ 100,000,000
Two Thousand Thirteen Revolving Credit Facility | Term Loan
Accounting Policies [Line Items]
Interest rate on borrowings under 2013 Credit Facility							if a Base Rate Loan, one and one half percent (1.50%) per annum and (ii) if a LIBOR Rate Loan, two and one half percent (2.50%) per annum;
Two Thousand Thirteen Revolving Credit Facility | Term Loan | Base Rate Margin
Accounting Policies [Line Items]
Variable interest rate basis spread on debt							1.50%
Two Thousand Thirteen Revolving Credit Facility | Term Loan | LIBOR Margin
Accounting Policies [Line Items]
Variable interest rate basis spread on debt							2.50%
Class A common stock
Accounting Policies [Line Items]
Amount approved under share purchase program		$ 20,000,000									$ 10,000,000
Additional share amount added to repurchase program		$ 10,000,000
Stock repurchased during period, shares | shares				0			0		0
Stock Repurchased And Retired During Period Shares | shares									2,500,000
Average price of repurchased shares | $ / shares									$ 5.08
Stock Repurchased And Retired During Period Value									$ 12,500,000
Employee Stock Options
Accounting Policies [Line Items]
Weighted average period for unrecognized compensation expense related to grants of stock options							1 year 6 months
Restricted Stock Units
Accounting Policies [Line Items]
Weighted average period for unrecognized compensation expense related to grants of stock options							1 year 4 months 24 days
Total unrecognized compensation expense related to grants of restricted stock and restricted stock units				$ 1,700,000			$ 1,700,000		1,700,000
Minimum
Accounting Policies [Line Items]
Stock options vesting period							1 year
Minimum | Restricted Stock Units
Accounting Policies [Line Items]
Stock options vesting period							1 year
Maximum
Accounting Policies [Line Items]
Stock options vesting period							4 years
Maximum | Restricted Stock Units
Accounting Policies [Line Items]
Stock options vesting period							4 years
Univision
Accounting Policies [Line Items]
Expiry year of long-term affiliation agreements							2021
Renewal period of affiliation agreements							2 years
Affiliate advertising minutes per hour for which entity has right to sell							6 minutes
Payment of sales representation fees to television stations				2,400,000	$ 2,600,000		$ 6,800,000	$ 7,800,000
Period to grant television station for terms of retransmission consent agreements							6 years
Retransmission consent agreements expiring date							Dec. 31, 2014
Amount due from television stations for carriage				$ 7,400,000			$ 7,400,000		$ 7,400,000
Common stock percentage held by Univision				10.00%			10.00%		10.00%
Common stock conversion ratio							100.00%
UniMas
Accounting Policies [Line Items]
Affiliate advertising minutes per hour for which entity has right to sell							4 minutes 30 seconds