Description of Business, Basis of Presentation and Summary of Significant Accounting Policies (Detail) $ in Thousands			3 Months Ended								9 Months Ended	12 Months Ended
	Oct. 12, 2016	Aug. 30, 2016 USD ($)	Dec. 31, 2016 USD ($) station	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($) station	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Sep. 30, 2016 USD ($)	Dec. 31, 2016 USD ($) segment station	Dec. 31, 2015 USD ($) segment station	Dec. 31, 2014 USD ($) station
Accounting Policies [Line Items]
Conversion ratio	0.125
Content costs												$ 427,780	$ 396,426	$ 433,596
Number of reportable segments | segment												2	1
Number of reporting units | segment												2	3
Proceeds from sale of assets or stations		$ 110,600										$ 106,935	$ 9,201	15,843
Gain on sale of assets or stations												95,695	(2,856)	1,342
Impairment charges related to decline in fair value of cost method investment												$ 0	19,364	0
Sales price of cost method investment														13,000
Advertising agency fees as a percentage of revenue												15.00%
Advertising expense												$ 4,900	3,900	1,900
Net revenue			$ 299,541	$ 286,136	$ 287,193	$ 268,530	$ 308,825	$ 289,441	$ 299,334	$ 271,079		1,141,400	1,168,679	1,263,423
Stock-based compensation expense												2,948	21,033	17,638
Trade revenue												37,691	39,237	34,876
Trade expenses												$ 36,158	$ 40,427	$ 36,753
Local Marketing Agreements
Accounting Policies [Line Items]
Number of radio stations owned or operated by Cumulus Media | station			5				6					5	6	6
Net revenue												$ 23,200	$ 24,500	$ 22,600
Other Income (Expense)
Accounting Policies [Line Items]
Gain recognized on sale of cost method investment														$ 3,200
Hurricane Katrina in 2005
Accounting Policies [Line Items]
Insurance proceeds received													14,600
Hurricane Katrina in 2005 | Other Income
Accounting Policies [Line Items]
Insurance proceeds received													12,400
Hurricane Katrina in 2005 | Corporate Expenses
Accounting Policies [Line Items]
Insurance proceeds received													2,200
Other Assets | Accounting Standards Update 2015-03
Accounting Policies [Line Items]
Debt issuance costs							$ 22,400						22,400
Long-term Debt | Accounting Standards Update 2015-03
Accounting Policies [Line Items]
Debt issuance costs							$ 22,400						$ 22,400
Prior Period Adjustment
Accounting Policies [Line Items]
Content costs					$ 3,600
Land and Building
Accounting Policies [Line Items]
Gain on sale of assets or stations											$ 94,000