Commitments and Contingencies - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended			3 Months Ended	9 Months Ended	0 Months Ended				0 Months Ended						0 Months Ended		9 Months Ended
	Sep. 30, 2014 Affiliate	Sep. 30, 2014 Exit Plan Contract Termination Accounts Payable and Accrued Expenses	Sep. 30, 2014 Exit Plan Contract Termination Non-current liabilities	Sep. 30, 2014 Exit Plan Contract Termination Corporate Expenses	Sep. 30, 2014 Exit Plan Contract Termination Corporate Expenses	Jan. 02, 2014 Merlin Media LLC	Apr. 25, 2014 Merlin Media LLC Put Option	Jan. 02, 2014 Merlin Media LLC Put Option	Jan. 02, 2014 Merlin Media LLC Put Option Station	Apr. 25, 2014 Merlin Media LLC Call Option	Apr. 25, 2014 Merlin Media LLC Call Option Maximum	Jan. 02, 2014 Merlin Media LLC Call Option Maximum	Jan. 02, 2014 Merlin Media LLC Call Option Minimum	Apr. 25, 2014 Universal Media Access, LLC	Apr. 25, 2014 Universal Media Access, LLC Station	Sep. 13, 2013 Strategic Promotional Partnership and Ad Sales Arrangement	Sep. 13, 2013 Strategic Promotional Partnership and Ad Sales Arrangement	Sep. 30, 2014 Arbitron
Supply Commitment [Line Items]
Industry fee to be credited in equal annual installments	$ 75.0
Industry fee refund for fees previously paid	70.5
Remaining aggregate obligation under the agreements with Arbitron																		136.4
Amount of promotion																75
Promotion period																5 years
Percentage ownership of fully diluted shares of Pulser equity																	15.00%
Number of radio stations	9,000								2						1
Monthly management fees, first year						0.3
Monthly management fees, second year						0.4
Monthly management fees, third year						0.5
Monthly management fees, fourth year						0.6
Amount under option agreement to settle management fees							14.8	71.0			14.8	70.0	50.0
Period after commencement date to settle management fees							2 years	4 years		18 months
Period to exercise option							10 days	10 days
Restructuring costs				0.1	5.2
Current restructuring liabilities		0.4
Noncurrent restructuring liabilities			4.4
Fixed fee under LMA														$ 1.4
Term under LMA														2 years