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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 926
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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.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
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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
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Goodwill and Identifiable Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Goodwill and Identifiable Intangible Assets [Abstract]
Goodwill	$ 200	$ 200		$ 200
Intangible assets, net [Abstract]
Impairment on intangible assets		589	$ 0
Enterprise Fund [Member]
Intangible assets, net [Abstract]
Impairment on intangible assets	0	589
Bancroft Fund [Member]
Intangible assets, net [Abstract]
Impairment on intangible assets		0
Ellsworth Fund [Member]
Intangible assets, net [Abstract]
Impairment on intangible assets		0
Investment Advisory Contract [Member] \| Enterprise Fund [Member]
Intangible assets, net [Abstract]
Identifiable intangible asset	1,300	1,300		1,900
Investment Advisory Contract [Member] \| Bancroft Fund Ltd. and the Ellsworth Growth and Income Fund Ltd. [Member]
Intangible assets, net [Abstract]
Identifiable intangible asset	$ 1,600	$ 1,600		$ 1,600