The Company and Significant Accounting Policies - Additional Information (Detail)			1 Months Ended			3 Months Ended			9 Months Ended
	Aug. 01, 2017 USD ($)	Aug. 02, 2013 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2017 USD ($) $ / shares shares	Sep. 30, 2016 USD ($) shares	Mar. 31, 2016 USD ($)	Sep. 30, 2017 USD ($) Segment shares	Sep. 30, 2016 USD ($) shares	Jul. 13, 2017 USD ($)	Jun. 30, 2017 USD ($)	Jan. 01, 2017 USD ($)	Dec. 16, 2013 USD ($) Derivative	May 31, 2013 USD ($)
Accounting Policies [Line Items]
Number of reportable segments | Segment									3
Restricted cash						$ 231,096,000			$ 231,096,000
Number of Class A common stock shares converted | shares									1
Share-based compensation expenses						1,100,000	$ 700,000		$ 3,100,000	$ 2,600,000
Total unrecognized compensation expense employee stock option plans						$ 100,000			$ 100,000
Shares of dilutive securities not included in computation of diluted income per share | shares						277	509		11,346	14,331
Amount approved under share purchase program											$ 15,000,000
Purchases of short-term investments										$ 30,000,000
Unamortized debt issuance costs			$ 2,365,000			$ 2,252,000			$ 2,252,000
Benefit in income tax expense due to adoption of new standard						(96,167,000)	$ (4,035,000)		(100,185,000)	(9,421,000)
Accounting Standards Update 2016-09
Accounting Policies [Line Items]
Cumulative-effect adjustment to deferred income taxes and total stockholders' equity													$ 2,400,000
Benefit in income tax expense due to adoption of new standard						600,000			800,000
Accounting Standards Update 2016-18
Accounting Policies [Line Items]
Restricted cash						231,100,000			$ 231,100,000
Interest Rate Swap Agreements
Accounting Policies [Line Items]
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 gain						500,000	600,000		$ 1,300,000	100,000
Interest paid related to interest rate swap						700,000			2,200,000
Unrealized gains or losses included in accumulated other comprehensive income or loss									0
Fair value of the interest rate swap liability			4,800,000			$ 2,700,000			$ 2,700,000
2013 Credit Facility
Accounting Policies [Line Items]
Effective interest rate						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
Additional restricted payments allowed for each anniversary of effective date of amendment under credit facility	$ 20,000,000
Net leverage ratio upper limit	5.5
Net leverage ratio lower limit	1
2013 Credit Facility | Interest Rate Swap Agreements
Accounting Policies [Line Items]
Interest rate swap inception date									Dec. 16, 2013
2013 Credit Facility | Base Rate Margin
Accounting Policies [Line Items]
Variable interest rate basis spread on debt									1.50%
2013 Credit Facility | LIBOR Margin
Accounting Policies [Line Items]
Variable interest rate basis spread on debt									2.50%
Term Loan B Facility
Accounting Policies [Line Items]
Repayment of loans			$ 20,000,000	$ 20,000,000	$ 20,000,000
Term Loan B Facility | 2013 Credit 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 expense		106.563%
Carrying value of term loan						$ 287,700,000			$ 287,700,000
Unamortized debt issuance costs						2,300,000			2,300,000
Estimated fair value of term loan						290,000,000			$ 290,000,000
Senior Secured Revolving Credit Facility | 2013 Credit Facility
Accounting Policies [Line Items]
Senior Secured debt															30,000,000
Maturity date of revolving credit facility									May 31, 2018
Term Loan A | 2013 Credit Facility
Accounting Policies [Line Items]
Senior Secured debt															20,000,000
Maturity date of revolving credit facility									Aug. 01, 2013
Term Loan And Revolving Credit Facility | 2013 Credit Facility
Accounting Policies [Line Items]
Additional borrowing capacity															$ 100,000,000
Term Loan | 2013 Credit Facility
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;
Term Loan | 2013 Credit Facility | Base Rate Margin
Accounting Policies [Line Items]
Variable interest rate basis spread on debt									1.50%
Term Loan | 2013 Credit Facility | LIBOR Margin
Accounting Policies [Line Items]
Variable interest rate basis spread on debt									2.50%
Chanclazo Studios, Inc
Accounting Policies [Line Items]
Cost method investments						$ 1,000,000			$ 1,000,000
Cost method investment ownership percentage						12.50%			12.50%
Cocina Vista, LLC
Accounting Policies [Line Items]
Cost method investments												$ 1,700,000
Cost method investment ownership percentage												34.35%
Investment milestone description									The Company is required to make a second investment of $1.5 million, for a total ownership interest of 51%, if Cocina achieves certain EBITDA goals.
Certificate of Deposit
Accounting Policies [Line Items]
Purchases of short-term investments								$ 30,000,000
Second Investment | Cocina Vista, LLC
Accounting Policies [Line Items]
Cost method investments												$ 1,500,000
Cost method investment ownership percentage												51.00%
Class A common stock
Accounting Policies [Line Items]
Number of shares repurchased | shares						300,000
Average price of repurchased shares | $ / shares						$ 5.62
Aggregate purchase price of repurchased shares						$ 1,800,000
Employee Stock Options
Accounting Policies [Line Items]
Weighted average period for recognition of unrecognized compensation expense									1 year
Restricted Stock Units
Accounting Policies [Line Items]
Weighted average period for recognition of unrecognized compensation expense									1 year 3 months 19 days
Total unrecognized compensation expense related to grants of restricted stock units						3,000,000			$ 3,000,000
Performance Restricted Stock Units
Accounting Policies [Line Items]
Share-based compensation expenses						0			$ 0
Vesting period									3 years
Minimum | Employee Stock Options
Accounting Policies [Line Items]
Vesting period									1 year
Minimum | Restricted Stock Units
Accounting Policies [Line Items]
Vesting period									1 year
Minimum | Performance Restricted Stock Units
Accounting Policies [Line Items]
Share award grant percentage									0.00%
Maximum
Accounting Policies [Line Items]
Stock repurchase program terminated, amount											$ 20,000,000
Maximum | 2013 Credit Facility
Accounting Policies [Line Items]
Restricted payments allowed under credit facility	$ 40,000,000
Maximum | Employee Stock Options
Accounting Policies [Line Items]
Vesting period									4 years
Maximum | Restricted Stock Units
Accounting Policies [Line Items]
Vesting period									4 years
Maximum | Performance Restricted Stock Units
Accounting Policies [Line Items]
Share award grant percentage									200.00%
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									4 minutes
Payment of sales representation fees to television stations						2,400,000	$ 2,600,000		$ 7,100,000	$ 7,400,000
Period to grant television stations for terms of retransmission consent agreements									6 years
Retransmission consent agreements expiring date									Dec. 31, 2014
Retransmission consent agreements extended expiration date									Sep. 30, 2017
Amount due from television stations for carriage						$ 4,000,000			$ 4,000,000
Common stock percentage held by Univision						10.00%			10.00%
UniMas
Accounting Policies [Line Items]
Affiliate advertising minutes per hour for which entity has right to sell									4 minutes 30 seconds