XML 112 R93.htm IDEA: XBRL DOCUMENT
v3.25.0.1

Benefit Plans - Defined Contribution and Other Plans (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 28, 2024 | Dec. 30, 2023 | Dec. 31, 2022
Supplemental Employee Retirement Plan |  |  |
Defined Contribution Plan Disclosure |  |  |
Discretionary contribution amount | $ 0.5 | $ 0.6 | $ 0.2
Other Assets |  |  |
Defined Contribution Plan Disclosure |  |  |
Recorded liability | 23.3 |  |
Other Long-term Liabilities |  |  |
Defined Contribution Plan Disclosure |  |  |
Plan assets | $ 23.3 |  |
401(K) Savings Plan |  |  |
Defined Contribution Plan Disclosure |  |  |
Employer matching contribution | 100.00% |  |
Discretionary matching contribution | 4.00% |  |
Discretionary matching contribution | 2.00% | 2.00% | 2.00%
Discretionary contribution amount | $ 6.5 | $ 7.7 | $ 5.5

X
- Definition Percentage of employees' gross pay for which the employer contributes an additional discretionary matching contribution to a defined contribution plan. + References No definition available. + Details
Name: | lfus_DefinedContributionPlanEmployerDiscretionaryMatchingContributionPercentOfEmployeesGrossPay
Namespace Prefix: | lfus_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of asset, recognized in statement of financial position, for assets in a defined contribution plan. + References No definition available. + Details
Name: | lfus_DefinedContributionPlanPlanAssets
Namespace Prefix: | lfus_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The carrying amount of the liability as of the balance sheet date to an individual under a deferred compensation arrangement. This amount may be the result of periodic accruals made over the period of active employment, or reflect termination benefits resulting contractual terms or a death benefit. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 710 -SubTopic 10 -Name Accounting Standards Codification -Section 30 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org/1943274/2147483043/710-10-30-1 + Details
Name: | us-gaap_DeferredCompensationArrangementWithIndividualRecordedLiability
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + 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 + Details
Name: | us-gaap_DefinedContributionPlanDisclosureLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of discretionary contributions made by an employer to a defined contribution plan. + References No definition available. + Details
Name: | us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan. + References No definition available. + Details
Name: | us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage employer matches of the employee's percentage contribution matched. + References No definition available. + Details
Name: | us-gaap_DefinedContributionPlanEmployerMatchingContributionPercentOfMatch
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_RetirementPlanTypeAxis=us-gaap_SupplementalEmployeeRetirementPlanDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BalanceSheetLocationAxis=us-gaap_OtherAssetsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BalanceSheetLocationAxis=lfus_OtherLongtermLiabilitiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanNameAxis=lfus_SavingsPlan401KMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |