Commitments and Contingencies - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Contingencies And Commitments [Line Items]
Lease commitment with media research and rating providers, aggregate amount	$ 19.2
Non-cancelable operating lease expiration term	2017-02
Total rent expense under operating leases	9.8	10.2	10.1
Bonus paid to executives	0.2	0.5	0
Facilities and Broadcast Equipment [Member]
Contingencies And Commitments [Line Items]
Non-cancelable operating lease expiration term	2050-11
Santa Monica [Member]
Contingencies And Commitments [Line Items]
Area under operating leases for corporate headquarters	16,000
Lease Expiration Year	2021
Los Angeles [Member]
Contingencies And Commitments [Line Items]
Area under operating leases for corporate headquarters	45,000
Lease Expiration Year	2016
Minimum [Member]
Contingencies And Commitments [Line Items]
Lease commitment with media research and rating providers, annual commitment range	0.2
Maximum [Member]
Contingencies And Commitments [Line Items]
Lease commitment with media research and rating providers, annual commitment range	$ 12.4