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

No definition available.

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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
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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 12 - Retirement, Savings and Deferred Compensation Plans (Details Textual) $ in Millions	3 Months Ended
	Mar. 31, 2026 USD ($) shares	Mar. 31, 2025 USD ($)	Dec. 31, 2025 USD ($)
Supplemental Employee Retirement Plan [Member]
Deferred Compensation Arrangement with Individual, Compensation Expense	$ 0.1	$ 0.1
Bel Fuse Inc. Employees' Savings Plan [Member]
Defined Contribution Plan, Cost	$ 0.7	$ 0.4
Bel Fuse Inc. Employees' Savings Plan [Member] \| Common Class A [Member]
Shares Held in Plan (in shares) \| shares	217,238
Bel Fuse Inc. Employees' Savings Plan [Member] \| Common Class B [Member]
Shares Held in Plan (in shares) \| shares	45,561
Nonqualified Deferred Compensation Plan [Member]
Deferred Compensation Arrangement, Vesting Age			65
Deferred Compensation Plan Assets	$ 1.7		$ 1.7