Supplemental Condensed Consolidated Financial Information (Condensed Consolidated Statements of Cash Flows) (Detail) - USD ($) $ in Thousands		3 Months Ended			9 Months Ended
	Aug. 30, 2016	Sep. 30, 2016	Jun. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Cash flows from operating activities:
Net income (loss)		$ 46,321		$ (542,179)	$ 32,958	$ (541,895)
Adjustments to reconcile net income (loss) to net cash (used in) provided by operating activities:
Depreciation and amortization					68,023	76,582
Amortization of debt issuance costs/discounts					7,325	7,112
Provision for doubtful accounts					1,188	2,417
(Gain) loss on sale of assets or stations					(97,155)	792
Impairment of intangible assets and goodwill		0		565,584	1,816	565,584
Impairment of intangible assets			$ 1,800		1,816	565,584
Impairment charges - equity interest in Pulser Media Inc.		0		18,308	0	19,364
Deferred income taxes					25,086	(58,520)
Stock-based compensation expense					2,403	20,047
(Earnings) loss from consolidated subsidiaries					0	0
Changes in assets and liabilities					(9,365)	(3,294)
Net cash provided by operating activities					32,279	88,189
Cash flows from investing activities:
Proceeds from sale of assets or stations	$ 110,600				106,935	3,055
Restricted cash					3,431	1,633
Capital expenditures					(16,704)	(15,817)
Net cash provided by (used in) investing activities					93,662	(11,129)
Cash flows from financing activities:
Intercompany transactions, net					0	0
Tax withholding payments on behalf of employees					0	(93)
Proceeds from exercise of warrants					3	7
Net cash provided by (used in) financing activities					3	(86)
Increase in cash and cash equivalents					125,944	76,974
Cash and cash equivalents at beginning of period					31,657	7,271
Cash and cash equivalents at end of period		157,601		84,245	157,601	84,245
Eliminations
Cash flows from operating activities:
Net income (loss)		(117,937)		843,056	(153,645)	813,134
Adjustments to reconcile net income (loss) to net cash (used in) provided by operating activities:
Depreciation and amortization					0	0
Amortization of debt issuance costs/discounts					0	0
Provision for doubtful accounts					0	0
(Gain) loss on sale of assets or stations					0	0
Impairment of intangible assets and goodwill				0	0	0
Impairment of intangible assets						0
Impairment charges - equity interest in Pulser Media Inc.				0		0
Deferred income taxes					0	0
Stock-based compensation expense					0	0
(Earnings) loss from consolidated subsidiaries					153,645	(813,134)
Changes in assets and liabilities					0	0
Net cash provided by operating activities					0	0
Cash flows from investing activities:
Proceeds from sale of assets or stations					0	0
Restricted cash					0	0
Capital expenditures					0	0
Net cash provided by (used in) investing activities					0	0
Cash flows from financing activities:
Intercompany transactions, net					0	0
Tax withholding payments on behalf of employees						0
Proceeds from exercise of warrants					0	0
Net cash provided by (used in) financing activities					0	0
Increase in cash and cash equivalents					0	0
Cash and cash equivalents at beginning of period					0	0
Cash and cash equivalents at end of period		0		0	0	0
Cumulus Media Inc. (Parent Guarantor)
Cash flows from operating activities:
Net income (loss)		46,321		(542,179)	32,958	(541,895)
Adjustments to reconcile net income (loss) to net cash (used in) provided by operating activities:
Depreciation and amortization					0	0
Amortization of debt issuance costs/discounts					0	0
Provision for doubtful accounts					0	0
(Gain) loss on sale of assets or stations					0	0
Impairment of intangible assets and goodwill				0	0	0
Impairment of intangible assets						0
Impairment charges - equity interest in Pulser Media Inc.				0		0
Deferred income taxes					(2,613)	(2,438)
Stock-based compensation expense					0	0
(Earnings) loss from consolidated subsidiaries					(36,878)	537,781
Changes in assets and liabilities					0	0
Net cash provided by operating activities					(6,533)	(6,552)
Cash flows from investing activities:
Proceeds from sale of assets or stations					0	0
Restricted cash					0	0
Capital expenditures					0	0
Net cash provided by (used in) investing activities					0	0
Cash flows from financing activities:
Intercompany transactions, net					6,530	6,545
Tax withholding payments on behalf of employees						0
Proceeds from exercise of warrants					3	7
Net cash provided by (used in) financing activities					6,533	6,552
Increase in cash and cash equivalents					0	0
Cash and cash equivalents at beginning of period					0	0
Cash and cash equivalents at end of period		0		0	0	0
Cumulus Media Holdings Inc. (Subsidiary Issuer)
Cash flows from operating activities:
Net income (loss)		47,562		(540,699)	36,878	(537,781)
Adjustments to reconcile net income (loss) to net cash (used in) provided by operating activities:
Depreciation and amortization					1,219	1,000
Amortization of debt issuance costs/discounts					7,183	6,970
Provision for doubtful accounts					0	0
(Gain) loss on sale of assets or stations					0	0
Impairment of intangible assets and goodwill				0	0	0
Impairment of intangible assets						0
Impairment charges - equity interest in Pulser Media Inc.				0		0
Deferred income taxes					(51,219)	120,572
Stock-based compensation expense					2,403	20,047
(Earnings) loss from consolidated subsidiaries					(117,962)	256,979
Changes in assets and liabilities					295,419	273,801
Net cash provided by operating activities					173,921	141,588
Cash flows from investing activities:
Proceeds from sale of assets or stations					0	0
Restricted cash					3,431	1,633
Capital expenditures					(868)	(2,244)
Net cash provided by (used in) investing activities					2,563	(611)
Cash flows from financing activities:
Intercompany transactions, net					(50,540)	(63,907)
Tax withholding payments on behalf of employees						(93)
Proceeds from exercise of warrants					0	0
Net cash provided by (used in) financing activities					(50,540)	(64,000)
Increase in cash and cash equivalents					125,944	76,977
Cash and cash equivalents at beginning of period					31,657	7,268
Cash and cash equivalents at end of period		157,601		84,245	157,601	84,245
Subsidiary Guarantors
Cash flows from operating activities:
Net income (loss)		70,810		(300,749)	117,962	(256,979)
Adjustments to reconcile net income (loss) to net cash (used in) provided by operating activities:
Depreciation and amortization					66,804	75,582
Amortization of debt issuance costs/discounts					0	0
Provision for doubtful accounts					1,188	2,417
(Gain) loss on sale of assets or stations					(97,155)	792
Impairment of intangible assets and goodwill				565,584	1,816	565,584
Impairment of intangible assets						565,584
Impairment charges - equity interest in Pulser Media Inc.				18,308		19,364
Deferred income taxes					79,620	(193,389)
Stock-based compensation expense					0	0
(Earnings) loss from consolidated subsidiaries					1,195	18,374
Changes in assets and liabilities					(306,539)	(278,592)
Net cash provided by operating activities					(135,109)	(46,847)
Cash flows from investing activities:
Proceeds from sale of assets or stations					106,935	3,055
Restricted cash					0	0
Capital expenditures					(15,836)	(13,573)
Net cash provided by (used in) investing activities					91,099	(10,518)
Cash flows from financing activities:
Intercompany transactions, net					44,010	57,362
Tax withholding payments on behalf of employees						0
Proceeds from exercise of warrants					0	0
Net cash provided by (used in) financing activities					44,010	57,362
Increase in cash and cash equivalents					0	(3)
Cash and cash equivalents at beginning of period					0	3
Cash and cash equivalents at end of period		0		0	0	0
Subsidiary Non-guarantors
Cash flows from operating activities:
Net income (loss)		(435)		(1,608)	(1,195)	(18,374)
Adjustments to reconcile net income (loss) to net cash (used in) provided by operating activities:
Depreciation and amortization					0	0
Amortization of debt issuance costs/discounts					142	142
Provision for doubtful accounts					0	0
(Gain) loss on sale of assets or stations					0	0
Impairment of intangible assets and goodwill				0	0	0
Impairment of intangible assets						0
Impairment charges - equity interest in Pulser Media Inc.				0		0
Deferred income taxes					(702)	16,735
Stock-based compensation expense					0	0
(Earnings) loss from consolidated subsidiaries					0	0
Changes in assets and liabilities					1,755	1,497
Net cash provided by operating activities					0	0
Cash flows from investing activities:
Proceeds from sale of assets or stations					0	0
Restricted cash					0	0
Capital expenditures					0	0
Net cash provided by (used in) investing activities					0	0
Cash flows from financing activities:
Intercompany transactions, net					0	0
Tax withholding payments on behalf of employees						0
Proceeds from exercise of warrants					0	0
Net cash provided by (used in) financing activities					0	0
Increase in cash and cash equivalents					0	0
Cash and cash equivalents at beginning of period					0	0
Cash and cash equivalents at end of period		$ 0		$ 0	$ 0	$ 0