Debt Issuance Expense

No definition available.

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Namespace Prefix:	lfus_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Line of Credit, Minimum Increase To Borrowing Amount

+ References

No definition available.

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Period Type:	duration

- Definition

Number Of Series

+ References

No definition available.

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Balance Type:	na
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

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- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Period Type:	instant

- Definition

Face (par) amount of debt instrument at time of issuance.

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- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

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- 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.

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- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

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- Definition

Nominal or face amount used to calculate payment on derivative.

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- Definition

Amount of cash paid for interest, excluding capitalized interest, classified as operating activity. Includes, but is not limited to, payment to settle zero-coupon bond for accreted interest of debt discount and debt instrument with insignificant coupon interest rate in relation to effective interest rate of borrowing attributable to accreted interest of debt discount.

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- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

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The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

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The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer.

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Debt - Narrative (Details)			3 Months Ended		12 Months Ended
Debt - Narrative (Details)	Mar. 12, 2026 USD ($)	Dec. 08, 2016 EUR (€)	Mar. 28, 2026 USD ($)	Mar. 29, 2025 USD ($)	Dec. 31, 2022 USD ($)	Dec. 27, 2025 USD ($)	Jul. 18, 2022 USD ($)	Jun. 30, 2022 USD ($)	May 12, 2022 USD ($)	Jan. 16, 2018 USD ($)	Nov. 15, 2017 USD ($) series	Feb. 15, 2017 USD ($)	Dec. 08, 2016 USD ($) series	Dec. 08, 2016 EUR (€) series
Debt Instrument
Letter of credit outstanding			$ 1,200,000
Cash paid during the period for interest			$ 10,482,000	$ 12,193,000
Hedged Portion \| Credit Agreement
Debt Instrument
Effective interest rate (as a percent)			3.88%
Interest rate swap agreement \| Designated as cash flow hedge \| Designated as Hedging Instrument
Debt Instrument
Notional amount of derivatives									$ 200,000,000
Term loan
Debt Instrument
Maximum borrowing capacity, credit facility	$ 300,000,000
Repayments of debt			$ 3,800,000
Long-term debt, gross			0			$ 266,250,000
Loan minimum increments	25,000,000
Term loan \| Revolving Credit Facility
Debt Instrument
Maximum borrowing capacity, credit facility	800,000,000							$ 700,000,000
Debt issuance costs			$ 2,200,000
Debt instrument, term			5 years
Line of Credit
Debt Instrument
Repayments of debt	62,500,000		$ 100,000,000.0
Long-term debt, gross	$ 200,000,000		200,000,000.0			100,000,000
Remaining borrowing capacity			598,800,000
Line of Credit \| Minimum
Debt Instrument
Commitment fee (as a percent)	0.10%
Line of Credit \| Minimum \| SOFR
Debt Instrument
Basis spread on variable rate (as a percent)	1.00%
Line of Credit \| Minimum \| Base Rate
Debt Instrument
Basis spread on variable rate (as a percent)	0.00%
Line of Credit \| Maximum
Debt Instrument
Commitment fee (as a percent)	0.175%
Line of Credit \| Maximum \| SOFR
Debt Instrument
Basis spread on variable rate (as a percent)	1.75%
Line of Credit \| Maximum \| Base Rate
Debt Instrument
Basis spread on variable rate (as a percent)	0.75%
Senior Notes \| Euro Senior Notes, Series A and B
Debt Instrument
Face amount of debt \| €														€ 212,000,000
Number of series \| series													2	2
Senior Notes \| Euro Senior Notes, Series A due 2023
Debt Instrument
Repayments of debt \| €		€ 117,000,000
Face amount of debt \| €														€ 117,000,000
Stated interest rate (as a percent)													1.14%	1.14%
Senior Notes \| Euro Senior Notes, Series B due 2028
Debt Instrument
Long-term debt, gross			109,545,000			111,977,000
Face amount of debt \| €														€ 95,000,000
Stated interest rate (as a percent)													1.83%	1.83%
Senior Notes \| U.S. Senior Notes, Series A and B
Debt Instrument
Face amount of debt													$ 125,000,000
Number of series \| series													2	2
Senior Notes \| U.S. Senior Notes, Series A due 2022
Debt Instrument
Face amount of debt												$ 25,000,000
Stated interest rate (as a percent)												3.03%
Senior Notes \| U.S. Senior Notes, Series B due 2027
Debt Instrument
Long-term debt, gross			100,000,000			100,000,000
Face amount of debt												$ 100,000,000
Stated interest rate (as a percent)												3.74%
Senior Notes \| U.S. Senior Notes, Series A
Debt Instrument
Repayments of debt					$ 25,000,000
Senior Notes \| U.S. Senior Notes A and B due 2025 and 2030
Debt Instrument
Face amount of debt											$ 175,000,000
Number of series \| series											2
Senior Notes \| U.S. Senior Notes, Series A due 2025
Debt Instrument
Face amount of debt										$ 50,000,000
Stated interest rate (as a percent)										3.48%
Senior Notes \| U.S. Senior Notes, Series B due 2030
Debt Instrument
Repayments of debt				$ 50,000,000
Long-term debt, gross			$ 125,000,000			$ 125,000,000
Face amount of debt										$ 125,000,000
Stated interest rate (as a percent)										3.78%
Senior Notes \| U.S Senior Notes, due 2032
Debt Instrument
Face amount of debt							$ 100,000,000
Stated interest rate (as a percent)							4.33%