Supplemental Condensed Consolidated Financial Information (Condensed Consolidated Balance Sheet) (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	$ 151,153	$ 131,259	$ 58,874	$ 31,657
Restricted cash	7,816	8,025
Accounts receivable, less allowance for doubtful accounts	213,642	231,585
Trade receivable	5,752	4,985
Assets held for sale	30,150	30,150
Prepaid expenses and other current assets	47,033	33,923
Total current assets	455,546	439,927
Property and equipment, net	156,834	162,063
Broadcast licenses	1,539,793	1,540,183
Other intangible assets, net	107,407	116,499
Goodwill	135,214	135,214
Investment in consolidated subsidiaries	0	0
Intercompany receivables	0	0
Other assets	18,684	18,805
Total assets	2,413,478	2,412,691
Accounts payable and accrued expenses	109,093	96,241
Trade payable	3,730	4,550
Total current liabilities	112,823	100,791
Long-term debt, excluding 7.75% Senior Notes, net of debt issuance costs/discounts of $29,909	1,782,352	1,780,357
7.75% Senior Notes, net of debt issuance costs of $6,200	604,409	603,800
Other liabilities	30,469	31,431
Intercompany payables	0	0
Accumulated losses in consolidated subsidiaries	0	0
Deferred income taxes	381,451	388,050
Total liabilities	2,911,504	2,904,429
Treasury stock, at cost	(229,310)	(229,310)
Additional paid-in-capital	1,625,353	1,624,815
Accumulated deficit	(1,894,390)	(1,887,564)
Total stockholders’ deficit	(498,026)	(491,738)
Total liabilities and stockholders’ deficit	2,413,478	2,412,691
Eliminations
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	0	0	0	0
Restricted cash	0	0
Accounts receivable, less allowance for doubtful accounts	0	0
Trade receivable	0	0
Assets held for sale	0	0
Prepaid expenses and other current assets	0	0
Total current assets	0	0
Property and equipment, net	0	0
Broadcast licenses	0	0
Other intangible assets, net	0	0
Goodwill	0	0
Investment in consolidated subsidiaries	(4,377,807)	(4,361,939)
Intercompany receivables	(1,980,391)	(1,951,856)
Other assets	(155,512)	(139,186)
Total assets	(6,513,710)	(6,452,981)
Accounts payable and accrued expenses	0	0
Trade payable	0	0
Total current liabilities	0	0
Long-term debt, excluding 7.75% Senior Notes, net of debt issuance costs/discounts of $29,909	0	0
7.75% Senior Notes, net of debt issuance costs of $6,200	0	0
Other liabilities	0	0
Intercompany payables	(1,980,391)	(1,951,856)
Accumulated losses in consolidated subsidiaries	(392,613)	(388,509)
Deferred income taxes	(155,512)	(139,186)
Total liabilities	(2,528,516)	(2,479,551)
Treasury stock, at cost	0	0
Additional paid-in-capital	(6,457,805)	(6,457,173)
Accumulated deficit	2,472,611	2,483,743
Total stockholders’ deficit	(3,985,194)	(3,973,430)
Total liabilities and stockholders’ deficit	(6,513,710)	(6,452,981)
Cumulus Media Inc. (Parent Guarantor)
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	0	0	0	0
Restricted cash	0	0
Accounts receivable, less allowance for doubtful accounts	0	0
Trade receivable	0	0
Assets held for sale	0	0
Prepaid expenses and other current assets	0	0
Total current assets	0	0
Property and equipment, net	0	0
Broadcast licenses	0	0
Other intangible assets, net	0	0
Goodwill	0	0
Investment in consolidated subsidiaries	0	0
Intercompany receivables	0	0
Other assets	0	0
Total assets	0	0
Accounts payable and accrued expenses	0	0
Trade payable	0	0
Total current liabilities	0	0
Long-term debt, excluding 7.75% Senior Notes, net of debt issuance costs/discounts of $29,909	0	0
7.75% Senior Notes, net of debt issuance costs of $6,200	0	0
Other liabilities	0	0
Intercompany payables	105,413	103,229
Accumulated losses in consolidated subsidiaries	392,613	388,509
Deferred income taxes	0	0
Total liabilities	498,026	491,738
Treasury stock, at cost	(229,310)	(229,310)
Additional paid-in-capital	1,625,353	1,624,815
Accumulated deficit	(1,894,390)	(1,887,564)
Total stockholders’ deficit	(498,026)	(491,738)
Total liabilities and stockholders’ deficit	0	0
Cumulus Media Holdings Inc. (Subsidiary Issuer)
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	151,153	131,259	58,874	31,657
Restricted cash	7,816	8,025
Accounts receivable, less allowance for doubtful accounts	0	0
Trade receivable	0	0
Assets held for sale	0	0
Prepaid expenses and other current assets	23,377	17,321
Total current assets	182,346	156,605
Property and equipment, net	6,569	4,431
Broadcast licenses	0	0
Other intangible assets, net	0	0
Goodwill	0	0
Investment in consolidated subsidiaries	3,374,977	3,348,992
Intercompany receivables	105,730	103,593
Other assets	20,128	21,631
Total assets	3,689,750	3,635,252
Accounts payable and accrued expenses	31,651	19,994
Trade payable	0	0
Total current liabilities	31,651	19,994
Long-term debt, excluding 7.75% Senior Notes, net of debt issuance costs/discounts of $29,909	1,782,352	1,780,357
7.75% Senior Notes, net of debt issuance costs of $6,200	604,409	603,800
Other liabilities	2,932	2,932
Intercompany payables	1,661,019	1,616,678
Accumulated losses in consolidated subsidiaries	0	0
Deferred income taxes	0	0
Total liabilities	4,082,363	4,023,761
Treasury stock, at cost	0	0
Additional paid-in-capital	277,212	275,107
Accumulated deficit	(669,825)	(663,616)
Total stockholders’ deficit	(392,613)	(388,509)
Total liabilities and stockholders’ deficit	3,689,750	3,635,252
Subsidiary Guarantors
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	0	0	0	0
Restricted cash	0	0
Accounts receivable, less allowance for doubtful accounts	0	0
Trade receivable	5,752	4,985
Assets held for sale	30,150	30,150
Prepaid expenses and other current assets	23,656	16,602
Total current assets	59,558	51,737
Property and equipment, net	150,265	157,632
Broadcast licenses	0	0
Other intangible assets, net	107,407	116,499
Goodwill	135,214	135,214
Investment in consolidated subsidiaries	1,002,830	1,012,947
Intercompany receivables	1,874,661	1,848,263
Other assets	153,751	135,996
Total assets	3,483,686	3,458,288
Accounts payable and accrued expenses	77,442	76,247
Trade payable	3,730	4,550
Total current liabilities	81,172	80,797
Long-term debt, excluding 7.75% Senior Notes, net of debt issuance costs/discounts of $29,909	0	0
7.75% Senior Notes, net of debt issuance costs of $6,200	0	0
Other liabilities	27,537	28,499
Intercompany payables	0	0
Accumulated losses in consolidated subsidiaries	0	0
Deferred income taxes	0	0
Total liabilities	108,709	109,296
Treasury stock, at cost	0	0
Additional paid-in-capital	4,199,550	4,191,057
Accumulated deficit	(824,573)	(842,065)
Total stockholders’ deficit	3,374,977	3,348,992
Total liabilities and stockholders’ deficit	3,483,686	3,458,288
Subsidiary Non-guarantors
Condensed Balance Sheet Statements, Captions [Line Items]
Cash and cash equivalents	0	0	$ 0	$ 0
Restricted cash	0	0
Accounts receivable, less allowance for doubtful accounts	213,642	231,585
Trade receivable	0	0
Assets held for sale	0	0
Prepaid expenses and other current assets	0	0
Total current assets	213,642	231,585
Property and equipment, net	0	0
Broadcast licenses	1,539,793	1,540,183
Other intangible assets, net	0	0
Goodwill	0	0
Investment in consolidated subsidiaries	0	0
Intercompany receivables	0	0
Other assets	317	364
Total assets	1,753,752	1,772,132
Accounts payable and accrued expenses	0	0
Trade payable	0	0
Total current liabilities	0	0
Long-term debt, excluding 7.75% Senior Notes, net of debt issuance costs/discounts of $29,909	0	0
7.75% Senior Notes, net of debt issuance costs of $6,200	0	0
Other liabilities	0	0
Intercompany payables	213,959	231,949
Accumulated losses in consolidated subsidiaries	0	0
Deferred income taxes	536,963	527,236
Total liabilities	750,922	759,185
Treasury stock, at cost	0	0
Additional paid-in-capital	1,981,043	1,991,009
Accumulated deficit	(978,213)	(978,062)
Total stockholders’ deficit	1,002,830	1,012,947
Total liabilities and stockholders’ deficit	1,753,752	1,772,132
Class A common stock
Condensed Balance Sheet Statements, Captions [Line Items]
Common stock	320	320
Class A common stock | Eliminations
Condensed Balance Sheet Statements, Captions [Line Items]
Common stock	0	0
Class A common stock | Cumulus Media Inc. (Parent Guarantor)
Condensed Balance Sheet Statements, Captions [Line Items]
Common stock	320	320
Class A common stock | Cumulus Media Holdings Inc. (Subsidiary Issuer)
Condensed Balance Sheet Statements, Captions [Line Items]
Common stock	0	0
Class A common stock | Subsidiary Guarantors
Condensed Balance Sheet Statements, Captions [Line Items]
Common stock	0	0
Class A common stock | Subsidiary Non-guarantors
Condensed Balance Sheet Statements, Captions [Line Items]
Common stock	0	0
Class C common stock
Condensed Balance Sheet Statements, Captions [Line Items]
Common stock	1	1
Class C common stock | Eliminations
Condensed Balance Sheet Statements, Captions [Line Items]
Common stock	0	0
Class C common stock | Cumulus Media Inc. (Parent Guarantor)
Condensed Balance Sheet Statements, Captions [Line Items]
Common stock	1	1
Class C common stock | Cumulus Media Holdings Inc. (Subsidiary Issuer)
Condensed Balance Sheet Statements, Captions [Line Items]
Common stock	0	0
Class C common stock | Subsidiary Guarantors
Condensed Balance Sheet Statements, Captions [Line Items]
Common stock	0	0
Class C common stock | Subsidiary Non-guarantors
Condensed Balance Sheet Statements, Captions [Line Items]
Common stock	$ 0	$ 0