Supplemental Condensed Consolidating Financial Information (Condensed Consolidating Statements of Operations) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Condensed Financial Statements, Captions [Line Items]
Net revenue	$ 329,247	$ 313,885	$ 328,247	$ 292,044	$ 275,458	$ 262,535	$ 270,306	$ 217,839	$ 1,263,423	$ 1,026,138	$ 1,002,272
Operating expenses:
Content costs									433,596	264,871	244,082
Other direct operating expenses									470,441	403,381	378,802
Depreciation and amortization									115,275	112,511	135,575
LMA fees									7,195	3,716	3,465
Corporate expenses (including stock-based compensation expense of $17,638, $10,804, and $11,894, respectively)									76,428	59,830	57,438
Impairment of intangible assets									0	0	125,985
Gain on sale of assets or stations									(1,342)	(3,685)	0
Gain on sale of stations or assets									(1,342)	(1,852)
Gain on derivative instrument									0	(1,852)	(12)
Total operating expenses									1,101,593	838,772	945,335
Operating income	42,375	41,900	58,433	19,122	31,317	62,820	73,952	19,277	161,830	187,366	56,937
Non-operating (expense) income:
Interest expense									(145,533)	(178,274)	(199,574)
Interest income									1,388	1,293	946
Loss on early extinguishment of debt									0	(34,934)	(2,432)
Other expense, net									4,338	(302)	(2,479)
Total non-operating expense, net									(139,807)	(212,217)	(203,539)
Income (loss) from continuing operations before income taxes	6,952	6,048	25,900	(16,877)	(42,837)	17,487	25,187	(24,688)	22,023	(24,851)	(146,602)
Income tax (expense) benefit									(10,254)	68,464	34,670
Income (loss) from continuing operations									11,769	43,613	(111,932)
Income (loss) from discontinued operations, net of taxes					106,263	(3,455)	11,987	17,675	0	132,470	79,203
Earnings (loss) from consolidated subsidiaries									0	0	0
Net income (loss)	3,361	2,540	15,137	(9,269)	150,933	7,037	27,101	(8,988)	11,769	176,083	(32,729)
Cumulus Media Inc. (Parent Guarantor)
Condensed Financial Statements, Captions [Line Items]
Net revenue									0	0	2,681
Operating expenses:
Content costs									0	0	0
Other direct operating expenses									0	0	0
Depreciation and amortization									0	0	2,671
LMA fees									0	0	0
Corporate expenses (including stock-based compensation expense of $17,638, $10,804, and $11,894, respectively)									0	0	57,438
Impairment of intangible assets											0
Gain on sale of assets or stations										0
Gain on sale of stations or assets									0	0
Gain on derivative instrument											0
Total operating expenses									0	0	60,109
Operating income									0	0	(57,428)
Non-operating (expense) income:
Interest expense									(9,349)	(11,765)	(3,708)
Interest income									0	0	0
Loss on early extinguishment of debt										0	0
Other expense, net									0	0	0
Total non-operating expense, net									(9,349)	(11,765)	(3,708)
Income (loss) from continuing operations before income taxes									(9,349)	(11,765)	(61,136)
Income tax (expense) benefit									3,739	4,706	0
Income (loss) from continuing operations									(5,610)	(7,059)	(61,136)
Income (loss) from discontinued operations, net of taxes										0	0
Earnings (loss) from consolidated subsidiaries									17,379	183,142	28,407
Net income (loss)									11,769	176,083	(32,729)
Cumulus Media Holdings Inc. (Subsidiary Issuer)
Condensed Financial Statements, Captions [Line Items]
Net revenue									479	1,063	0
Operating expenses:
Content costs									0	0	0
Other direct operating expenses									0	0	0
Depreciation and amortization									1,619	1,913	0
LMA fees									0	0	0
Corporate expenses (including stock-based compensation expense of $17,638, $10,804, and $11,894, respectively)									76,428	59,830	0
Impairment of intangible assets											0
Gain on sale of assets or stations										0
Gain on sale of stations or assets									0	0
Gain on derivative instrument											0
Total operating expenses									78,047	61,743	0
Operating income									(77,568)	(60,680)	0
Non-operating (expense) income:
Interest expense									(135,920)	(166,445)	(196,982)
Interest income									0	1,289	946
Loss on early extinguishment of debt										(34,934)	(2,432)
Other expense, net									0	0	0
Total non-operating expense, net									(135,920)	(200,090)	(198,468)
Income (loss) from continuing operations before income taxes									(213,488)	(260,770)	(198,468)
Income tax (expense) benefit									81,993	104,308	0
Income (loss) from continuing operations									(131,495)	(156,462)	(198,468)
Income (loss) from discontinued operations, net of taxes										0	0
Earnings (loss) from consolidated subsidiaries									148,874	339,604	226,875
Net income (loss)									17,379	183,142	28,407
Subsidiary Guarantors
Condensed Financial Statements, Captions [Line Items]
Net revenue									1,262,944	1,025,075	999,591
Operating expenses:
Content costs									433,596	264,871	244,082
Other direct operating expenses									468,349	401,122	375,576
Depreciation and amortization									113,656	110,598	132,904
LMA fees									7,195	3,716	3,465
Corporate expenses (including stock-based compensation expense of $17,638, $10,804, and $11,894, respectively)									0	0	0
Impairment of intangible assets											111,279
Gain on sale of assets or stations										(3,685)
Gain on sale of stations or assets									(1,342)	(1,852)
Gain on derivative instrument											(12)
Total operating expenses									1,021,454	774,770	867,294
Operating income									241,490	250,305	132,297
Non-operating (expense) income:
Interest expense									0	0	1,116
Interest income									1,388	4	0
Loss on early extinguishment of debt										0	0
Other expense, net									4,338	(302)	(2,479)
Total non-operating expense, net									5,726	(298)	(1,363)
Income (loss) from continuing operations before income taxes									247,216	250,007	130,934
Income tax (expense) benefit									(96,928)	(41,479)	25,290
Income (loss) from continuing operations									150,288	208,528	156,224
Income (loss) from discontinued operations, net of taxes										132,470	50,336
Earnings (loss) from consolidated subsidiaries									(1,414)	(1,394)	20,315
Net income (loss)									148,874	339,604	226,875
Subsidiary Non- guarantors
Condensed Financial Statements, Captions [Line Items]
Net revenue									0	0	0
Operating expenses:
Content costs									0	0	0
Other direct operating expenses									2,092	2,259	3,226
Depreciation and amortization									0	0	0
LMA fees									0	0	0
Corporate expenses (including stock-based compensation expense of $17,638, $10,804, and $11,894, respectively)									0	0	0
Impairment of intangible assets											14,706
Gain on sale of assets or stations										0
Gain on sale of stations or assets									0	0
Gain on derivative instrument											0
Total operating expenses									2,092	2,259	17,932
Operating income									(2,092)	(2,259)	(17,932)
Non-operating (expense) income:
Interest expense									(264)	(64)	0
Interest income									0	0	0
Loss on early extinguishment of debt										0	0
Other expense, net									0	0	0
Total non-operating expense, net									(264)	(64)	0
Income (loss) from continuing operations before income taxes									(2,356)	(2,323)	(17,932)
Income tax (expense) benefit									942	929	9,380
Income (loss) from continuing operations									(1,414)	(1,394)	(8,552)
Income (loss) from discontinued operations, net of taxes										0	28,867
Earnings (loss) from consolidated subsidiaries									0	0
Net income (loss)									(1,414)	(1,394)	20,315
Eliminations
Condensed Financial Statements, Captions [Line Items]
Net revenue									0	0	0
Operating expenses:
Content costs									0	0	0
Other direct operating expenses									0	0	0
Depreciation and amortization									0	0	0
LMA fees									0	0	0
Corporate expenses (including stock-based compensation expense of $17,638, $10,804, and $11,894, respectively)									0	0	0
Impairment of intangible assets											0
Gain on sale of assets or stations										0
Gain on sale of stations or assets									0	0
Gain on derivative instrument											0
Total operating expenses									0	0	0
Operating income									0	0	0
Non-operating (expense) income:
Interest expense									0	0	0
Interest income									0	0	0
Loss on early extinguishment of debt										0	0
Other expense, net									0	0	0
Total non-operating expense, net									0	0	0
Income (loss) from continuing operations before income taxes									0	0	0
Income tax (expense) benefit									0	0	0
Income (loss) from continuing operations									0	0	0
Income (loss) from discontinued operations, net of taxes										0	0
Earnings (loss) from consolidated subsidiaries									(164,839)	(521,352)	(275,597)
Net income (loss)									$ (164,839)	$ (521,352)	$ (275,597)