Supplemental Condensed Consolidated Financial Information (Condensed Consolidated Statements of Cash Flows) (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Cash flows from operating activities:
Net (loss) income	$ 5,672	$ 1,066	$ (1,723)	$ (13,363)
Adjustments to reconcile net (loss) income to net cash (used in) provided by operating activities:
Depreciation and amortization			32,402	46,066
Amortization of debt issuance costs/discounts			5,055	4,860
Provision for doubtful accounts			1,993	493
Gain on sale of assets or stations			(2,502)	(3,141)
Impairment of intangible assets and goodwill				1,816
Deferred income taxes			1,206	(7,918)
Stock-based compensation expense			1,068	1,668
(Earnings) loss from consolidated subsidiaries			0	0
Changes in assets and liabilities			(20,559)	(5,471)
Net cash provided by operating activities			16,940	25,010
Cash flows from investing activities:
Proceeds from sale of assets or stations			6,090	4,254
Restricted cash			203	336
Capital expenditures			(13,203)	(11,462)
Net cash used in investing activities			(6,910)	(6,872)
Cash flows from financing activities:
Intercompany transactions, net			0	0
Deferred financing costs			(94)	0
Proceeds from exercise of warrants			0	3
Net cash (used in) provided by financing activities			(94)	3
Increase in cash and cash equivalents			9,936	18,141
Cash and cash equivalents at beginning of period			131,259	31,657
Cash and cash equivalents at end of period	141,195	49,798	141,195	49,798
Eliminations
Cash flows from operating activities:
Net (loss) income	(117,993)	(32,357)	(128,298)	(31,957)
Adjustments to reconcile net (loss) income 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 on sale of assets or stations			0	0
Impairment of intangible assets and goodwill				0
Deferred income taxes			0	0
Stock-based compensation expense			0	0
(Earnings) loss from consolidated subsidiaries			128,298	31,957
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 used in investing activities			0	0
Cash flows from financing activities:
Intercompany transactions, net			0	0
Deferred financing costs			0
Proceeds from exercise of warrants				0
Net cash (used in) provided by 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 (loss) income	5,672	1,066	(1,723)	(13,363)
Adjustments to reconcile net (loss) income 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 on sale of assets or stations			0	0
Impairment of intangible assets and goodwill				0
Deferred income taxes			1,742	(1,742)
Stock-based compensation expense			0	0
(Earnings) loss from consolidated subsidiaries			(4,374)	10,750
Changes in assets and liabilities			2,171	0
Net cash provided by operating activities			(2,184)	(4,355)
Cash flows from investing activities:
Proceeds from sale of assets or stations			0	0
Restricted cash			0	0
Capital expenditures			0	0
Net cash used in investing activities			0	0
Cash flows from financing activities:
Intercompany transactions, net			2,184	4,352
Deferred financing costs			0
Proceeds from exercise of warrants				3
Net cash (used in) provided by financing activities			2,184	4,355
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 (loss) income	10,596	2,429	4,374	(10,750)
Adjustments to reconcile net (loss) income to net cash (used in) provided by operating activities:
Depreciation and amortization			604	818
Amortization of debt issuance costs/discounts			4,946	4,765
Provision for doubtful accounts			0	0
Gain on sale of assets or stations			0	0
Impairment of intangible assets and goodwill				0
Deferred income taxes			35,392	(35,080)
Stock-based compensation expense			1,068	1,668
(Earnings) loss from consolidated subsidiaries			(125,741)	(43,408)
Changes in assets and liabilities			140,987	149,483
Net cash provided by operating activities			61,630	67,496
Cash flows from investing activities:
Proceeds from sale of assets or stations			0	0
Restricted cash			203	336
Capital expenditures			(5,468)	(377)
Net cash used in investing activities			(5,265)	(41)
Cash flows from financing activities:
Intercompany transactions, net			(46,335)	(49,314)
Deferred financing costs			(94)
Proceeds from exercise of warrants				0
Net cash (used in) provided by financing activities			(46,429)	(49,314)
Increase in cash and cash equivalents			9,936	18,141
Cash and cash equivalents at beginning of period			131,259	31,657
Cash and cash equivalents at end of period	141,195	49,798	141,195	49,798
Subsidiary Guarantors
Cash flows from operating activities:
Net (loss) income	108,656	30,293	125,741	43,408
Adjustments to reconcile net (loss) income to net cash (used in) provided by operating activities:
Depreciation and amortization			31,798	45,248
Amortization of debt issuance costs/discounts			0	0
Provision for doubtful accounts			1,993	493
Gain on sale of assets or stations			(2,502)	(3,141)
Impairment of intangible assets and goodwill				1,816
Deferred income taxes			(36,447)	29,372
Stock-based compensation expense			0	0
(Earnings) loss from consolidated subsidiaries			1,817	701
Changes in assets and liabilities			(164,906)	(156,028)
Net cash provided by operating activities			(42,506)	(38,131)
Cash flows from investing activities:
Proceeds from sale of assets or stations			6,090	4,254
Restricted cash			0	0
Capital expenditures			(7,735)	(11,085)
Net cash used in investing activities			(1,645)	(6,831)
Cash flows from financing activities:
Intercompany transactions, net			44,151	44,962
Deferred financing costs			0
Proceeds from exercise of warrants				0
Net cash (used in) provided by financing activities			44,151	44,962
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
Subsidiary Non-guarantors
Cash flows from operating activities:
Net (loss) income	(1,259)	(365)	(1,817)	(701)
Adjustments to reconcile net (loss) income to net cash (used in) provided by operating activities:
Depreciation and amortization			0	0
Amortization of debt issuance costs/discounts			109	95
Provision for doubtful accounts			0	0
Gain on sale of assets or stations			0	0
Impairment of intangible assets and goodwill				0
Deferred income taxes			519	(468)
Stock-based compensation expense			0	0
(Earnings) loss from consolidated subsidiaries			0	0
Changes in assets and liabilities			1,189	1,074
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 used in investing activities			0	0
Cash flows from financing activities:
Intercompany transactions, net			0	0
Deferred financing costs			0
Proceeds from exercise of warrants				0
Net cash (used in) provided by 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