The age of employees for contributions to become fully vested under deferred compensation arrangement.

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- Definition

The number of shares of the company's common stock owned by the plan.

+ References

No definition available.

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- Definition

The compensation expense recognized during the period pertaining to the deferred compensation arrangement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 710
-SubTopic 10
-Name Accounting Standards Codification
-Section 30
-Paragraph 1
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- Definition

Carrying amount as of the balance sheet date of assets held under deferred compensation agreements.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
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-Publisher FASB
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- Definition

Amount of cost for defined contribution plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 70
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480794/715-70-50-1

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Note 13 - Retirement, Savings and Deferred Compensation Plans (Details Textual) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025 USD ($) shares	Jun. 30, 2024 USD ($)	Jun. 30, 2025 USD ($) shares	Jun. 30, 2024 USD ($)	Dec. 31, 2024 USD ($)
Supplemental Employee Retirement Plan [Member]
Deferred Compensation Arrangement with Individual, Compensation Expense	$ 0.1	$ 0.1	$ 0.1	$ 0.2
Bel Fuse Inc. Employees' Savings Plan [Member]
Defined Contribution Plan, Cost	$ 0.3	0.3	$ 0.8	0.9
Bel Fuse Inc. Employees' Savings Plan [Member] \| Common Class A [Member]
Shares Held in Plan (in shares) \| shares	249,184		249,184
Bel Fuse Inc. Employees' Savings Plan [Member] \| Common Class B [Member]
Shares Held in Plan (in shares) \| shares	49,971		49,971
Nonqualified Deferred Compensation Plan [Member]
Deferred Compensation Arrangement, Vesting Age	65		65
Deferred Compensation Plan Assets	$ 1.5		$ 1.5		$ 1.3
Nonqualified Deferred Compensation Plan [Member] \| Maximum [Member]
Deferred Compensation Arrangement with Individual, Compensation Expense	$ 0.1	$ 0.1	$ 0.1	$ 0.1