Amount after amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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-Topic 350
-SubTopic 30
-Section 50
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- Definition

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
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- Definition

The amount of impairment loss recognized in the period resulting from the write-down of the carrying amount of a finite-lived intangible asset to fair value.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
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-Topic 350
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Goodwill and Identifiable Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Goodwill and Identifiable Intangible Assets [Abstract]
Goodwill	$ 0.2		$ 0.2		$ 0.2
Intangible assets, net [Abstract]
Impairment on intangible assets	0.0	$ 0.0	0.0	$ 0.0
Investment Advisory Contract [Member] \| Gabelli Enterprise Mergers and Acquisitions Fund [Member]
Intangible assets, net [Abstract]
Identifiable intangible asset	1.9		1.9		1.9
Investment Advisory Contract [Member] \| Bancroft Fund Ltd. and the Ellsworth Growth and Income Fund Ltd. [Member]
Intangible assets, net [Abstract]
Identifiable intangible asset	$ 1.6		$ 1.6		$ 1.6