$LFUS
LITTELFUSE INC /DE Stock $lfus

$lfus Overview Financials Valuation SEC Filings Company Website

2018 Q4 Form 10-K Financial Statement

#000088933120000014 Filed on February 21, 2020

Income Statement

Concept	2018 Q4	2018 Q3	2018 Q2
Revenue	$402.3M	$439.2M	$459.2M
YoY Change	31.96%	40.16%	60.87%
Cost Of Revenue	$247.1M	$259.6M	$290.2M
YoY Change	38.66%	40.9%	68.92%
Gross Profit	$154.3M	$179.6M	$169.0M
YoY Change	21.89%	34.38%	48.69%
Gross Profit Margin	38.37%	40.89%	36.8%
Selling, General & Admin	$55.80M	$69.78M	$73.24M
YoY Change	-0.18%	22.94%	56.83%
% of Gross Profit	36.15%	38.86%	43.34%
Research & Development	$21.50M	$20.45M	$22.75M
YoY Change	58.09%	70.58%	87.21%
% of Gross Profit	13.93%	11.39%	13.46%
Depreciation & Amortization	$27.10M	$26.26M	$26.19M
YoY Change	65.24%	64.67%	73.77%
% of Gross Profit	17.56%	14.62%	15.5%
Operating Expenses	$102.3M	$103.4M	$109.4M
YoY Change	34.78%	37.74%	68.78%
Operating Profit	$51.63M	$76.23M	$59.62M
YoY Change	1.67%	30.06%	22.05%
Interest Expense	-$11.10M	$5.775M	$5.782M
YoY Change	50.0%	66.57%	85.32%
% of Operating Profit	-21.5%	7.58%	9.7%
Other Income/Expense, Net	-$800.0K	-$1.259M	$1.678M
YoY Change	-366.67%	-224.28%	1107.19%
Pretax Income	$39.80M	$68.21M	$52.32M
YoY Change	-8.92%	22.85%	10.31%
Income Tax	$3.900M	$14.67M	$9.992M
% Of Pretax Income	9.8%	21.5%	19.1%
Net Earnings	$32.67M	$53.55M	$42.33M
YoY Change	-401.92%	25.08%	8.83%
Net Earnings / Revenue	8.12%	12.19%	9.22%
Basic Earnings Per Share		$2.13	$1.69
Diluted Earnings Per Share	$1.292M	$2.10	$1.67
COMMON SHARES
Basic Shares Outstanding	25.16M shares	25.11M shares	25.00M shares
Diluted Shares Outstanding		25.47M shares	25.40M shares

Balance Sheet

Concept	2018 Q4	2018 Q3	2018 Q2
SHORT-TERM ASSETS
Cash & Short-Term Investments	$489.8M	$498.3M	$408.2M
YoY Change	13.99%	54.8%	46.83%
Cash & Equivalents	$489.7M	$498.2M	$408.1M
Short-Term Investments	$0.00	$0.00	$0.00
Other Short-Term Assets	$49.30M	$48.70M	$45.70M
YoY Change	31.47%	-6.17%	251.54%
Inventory	$258.2M	$247.3M	$239.2M
Prepaid Expenses
Receivables	$232.9M	$251.6M	$260.4M
Other Receivables	$2.300M	$6.800M	$4.700M
Total Short-Term Assets	$1.033B	$1.053B	$958.2M
YoY Change	30.31%	38.62%	51.08%
LONG-TERM ASSETS
Property, Plant & Equipment	$339.9M	$343.9M	$338.8M
YoY Change	35.64%	40.43%	51.27%
Goodwill	$826.7M	$830.4M	$832.2M
YoY Change	82.33%	84.06%	94.29%
Intangibles	$361.5M	$377.2M	$390.1M
YoY Change	77.32%
Long-Term Investments	$11.60M	$29.10M	$31.30M
YoY Change	5.45%	144.54%	167.52%
Other Assets	$20.97M	$21.40M	$27.11M
YoY Change	22.85%	140.11%	164.39%
Total Long-Term Assets	$1.582B	$1.611B	$1.630B
YoY Change	66.9%	70.85%	79.13%
TOTAL ASSETS
Total Short-Term Assets	$1.033B	$1.053B	$958.2M
Total Long-Term Assets	$1.582B	$1.611B	$1.630B
Total Assets	$2.614B	$2.663B	$2.588B
YoY Change	50.24%	56.47%	67.61%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$126.3M	$129.9M	$127.3M
YoY Change	24.04%	25.06%	44.06%
Accrued Expenses	$138.4M	$74.08M	$66.34M
YoY Change	37.83%	40.35%	38.65%
Deferred Revenue
YoY Change
Short-Term Debt	$0.00	$0.00	$0.00
YoY Change
Long-Term Debt Due	$10.00M	$10.08M	$10.06M
YoY Change	60.0%	7.48%	60.96%
Total Short-Term Liabilities	$295.3M	$303.9M	$267.2M
YoY Change	31.35%	34.37%	50.79%
LONG-TERM LIABILITIES
Long-Term Debt	$684.7M	$690.6M	$687.5M
YoY Change	39.92%	40.3%	48.09%
Other Long-Term Liabilities	$72.23M	$67.40M	$76.07M
YoY Change	15.42%	156.97%	212.07%
Total Long-Term Liabilities	$757.0M	$758.0M	$763.6M
YoY Change	37.15%	46.2%	56.27%
TOTAL LIABILITIES
Total Short-Term Liabilities	$295.3M	$303.9M	$267.2M
Total Long-Term Liabilities	$757.0M	$758.0M	$763.6M
Total Liabilities	$1.052B	$1.062B	$1.031B
YoY Change	35.47%	42.61%	54.81%
SHAREHOLDERS EQUITY
Retained Earnings	$856.5M	$834.6M	$791.8M
YoY Change	18.61%	12.57%	18.93%
Common Stock	$254.0K	$254.0K	$253.0K
YoY Change	10.92%	10.92%	10.96%
Preferred Stock
YoY Change
Treasury Stock (at cost)	$116.5M	$48.55M	$48.34M
YoY Change	182.01%	17.66%	31.2%
Treasury Stock Shares	868.0K shares	476.0K shares	$475.1K
Shareholders Equity	$1.478B	$1.519B	$1.470B
YoY Change
Total Liabilities & Shareholders Equity	$2.614B	$2.663B	$2.588B
YoY Change	50.24%	56.47%	67.61%

Cashflow Statement

Concept	2018 Q4	2018 Q3	2018 Q2
OPERATING ACTIVITIES
Net Income	$32.67M	$53.55M	$42.33M
YoY Change	-401.92%	25.08%	8.83%
Depreciation, Depletion And Amortization	$27.10M	$26.26M	$26.19M
YoY Change	65.24%	64.67%	73.77%
Cash From Operating Activities	$79.70M	$111.2M	$71.60M
YoY Change	-9.33%	57.28%	212.08%
INVESTING ACTIVITIES
Capital Expenditures	-$18.90M	-$15.60M	-$22.40M
YoY Change	8.62%	-1.89%	-280.98%
Acquisitions
YoY Change
Other Investing Activities	$5.100M	-$2.200M	-$3.900M
YoY Change	920.0%	-215.79%	-59.79%
Cash From Investing Activities	-$13.60M	-$17.90M	-$26.30M
YoY Change	-19.53%	27.86%	19.02%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	-73.40M	-900.0K	-44.10M
YoY Change	303.3%	-93.08%	-1601.02%
NET CHANGE
Cash From Operating Activities	79.70M	111.2M	71.60M
Cash From Investing Activities	-13.60M	-17.90M	-26.30M
Cash From Financing Activities	-73.40M	-900.0K	-44.10M
Net Change In Cash	-7.300M	92.40M	1.200M
YoY Change	-113.83%	111.44%	-68.28%
FREE CASH FLOW
Cash From Operating Activities	$79.70M	$111.2M	$71.60M
Capital Expenditures	-$18.90M	-$15.60M	-$22.40M
Free Cash Flow	$98.60M	$126.8M	$94.00M
YoY Change	-6.36%	46.42%	789.65%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
CY2019	dei	Amendment Flag AmendmentFlag	false
CY2019	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-28
CY2019	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	FY
CY2019	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2019
CY2019	dei	Document Period End Date DocumentPeriodEndDate	2019-12-28
CY2019	dei	Entity Central Index Key EntityCentralIndexKey	0000889331
CY2019	dei	Entity Registrant Name EntityRegistrantName	LITTELFUSE INC /DE
CY2018Q4	us-gaap	Allowance For Doubtful Accounts Receivable Current AllowanceForDoubtfulAccountsReceivableCurrent	36038000	USD
CY2019Q4	us-gaap	Allowance For Doubtful Accounts Receivable Current AllowanceForDoubtfulAccountsReceivableCurrent	42043000	USD
CY2018Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.01
CY2018Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	34000000	shares
CY2019Q4	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	34000000	shares
CY2018Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	25641959	shares
CY2019Q4	us-gaap	Common Stock Shares Issued CommonStockSharesIssued	25855203	shares
CY2018Q4	us-gaap	Treasury Stock Shares TreasuryStockShares	868045	shares
CY2019Q4	us-gaap	Treasury Stock Shares TreasuryStockShares	1473901	shares
CY2019	dei	Document Type DocumentType	10-K
CY2019	dei	Document Annual Report DocumentAnnualReport	true
CY2019	dei	Document Transition Report DocumentTransitionReport	false
CY2019	dei	Entity File Number EntityFileNumber	0-20388
CY2019	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	DE
CY2019	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	36-3795742
CY2019	dei	Entity Address Address Line1 EntityAddressAddressLine1	8755 West Higgins Road
CY2019	dei	Entity Address Address Line2 EntityAddressAddressLine2	Suite 500
CY2019	dei	Entity Address City Or Town EntityAddressCityOrTown	Chicago
CY2019	dei	Entity Address State Or Province EntityAddressStateOrProvince	IL
CY2019	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	60631
CY2019	dei	City Area Code CityAreaCode	773
CY2019	dei	Local Phone Number LocalPhoneNumber	628-1000
CY2019	dei	Security12b Title Security12bTitle	Common Stock, $0.01 par value
CY2019	dei	Trading Symbol TradingSymbol	LFUS
CY2019	dei	Security Exchange Name SecurityExchangeName	NASDAQ
CY2019	dei	Entity Well Known Seasoned Issuer EntityWellKnownSeasonedIssuer	Yes
CY2019	dei	Entity Voluntary Filers EntityVoluntaryFilers	No
CY2019	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
CY2019	dei	Entity Interactive Data Current EntityInteractiveDataCurrent	Yes
CY2019	dei	Entity Filer Category EntityFilerCategory	Large Accelerated Filer
CY2019	dei	Entity Small Business EntitySmallBusiness	false
CY2019	dei	Entity Emerging Growth Company EntityEmergingGrowthCompany	false
CY2019	dei	Entity Shell Company EntityShellCompany	false
CY2019Q2	dei	Entity Public Float EntityPublicFloat	4264278799	USD
CY2020Q1	dei	Entity Common Stock Shares Outstanding EntityCommonStockSharesOutstanding	24425955	shares
CY2019Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	531139000	USD
CY2018Q4	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	489733000	USD
CY2019Q4	us-gaap	Short Term Investments ShortTermInvestments	44000	USD
CY2018Q4	us-gaap	Short Term Investments ShortTermInvestments	34000	USD
CY2019Q4	us-gaap	Accounts Receivable Net Current AccountsReceivableNetCurrent	202309000	USD
CY2018Q4	us-gaap	Accounts Receivable Net Current AccountsReceivableNetCurrent	232892000	USD
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CY2018Q4	us-gaap	Inventory Net InventoryNet	258228000	USD
CY2019Q4	us-gaap	Prepaid Taxes PrepaidTaxes	4831000	USD
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CY2019Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	21918000	USD
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CY2019Q4	us-gaap	Long Term Debt Current LongTermDebtCurrent	10000000	USD
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CY2017	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	130430000	USD
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CY2019	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	5.66
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CY2018	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Gain Loss Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax	-877000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Reclassification Adjustment From Aoci Pension And Other Postretirement Benefit Plans For Net Gain Loss Net Of Tax OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossNetOfTax	-1147000	USD
CY2019	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	0	USD
CY2018	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	0	USD
CY2017	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-974000	USD
CY2019	us-gaap	Other Comprehensive Income Foreign Currency Transaction And Translation Adjustment Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent	-812000	USD
CY2018	us-gaap	Other Comprehensive Income Foreign Currency Transaction And Translation Adjustment Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent	-25338000	USD
CY2017	us-gaap	Other Comprehensive Income Foreign Currency Transaction And Translation Adjustment Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeForeignCurrencyTransactionAndTranslationAdjustmentNetOfTaxPortionAttributableToParent	10738000	USD
CY2019	us-gaap	Profit Loss ProfitLoss	139082000	USD
CY2018	us-gaap	Profit Loss ProfitLoss	164565000	USD
CY2017	us-gaap	Profit Loss ProfitLoss	119519000	USD
CY2019	us-gaap	Depreciation Depreciation	52477000	USD
CY2018	us-gaap	Depreciation Depreciation	51003000	USD
CY2017	us-gaap	Depreciation Depreciation	38311000	USD
CY2019	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	40026000	USD
CY2018	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	52190000	USD
CY2017	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	24700000	USD
CY2019	us-gaap	Asset Impairment Charges AssetImpairmentCharges	322000	USD
CY2018	us-gaap	Asset Impairment Charges AssetImpairmentCharges	2218000	USD
CY2017	us-gaap	Asset Impairment Charges AssetImpairmentCharges	0	USD
CY2019	us-gaap	Increase Decrease In Contract With Customer Liability IncreaseDecreaseInContractWithCustomerLiability	-318000	USD
CY2018	us-gaap	Increase Decrease In Contract With Customer Liability IncreaseDecreaseInContractWithCustomerLiability	3965000	USD
CY2017	us-gaap	Increase Decrease In Contract With Customer Liability IncreaseDecreaseInContractWithCustomerLiability	0	USD
CY2019	lfus	Inventory Charge Related To Step Up In Cost Basis InventoryChargeRelatedToStepUpInCostBasis	0	USD
CY2018	lfus	Inventory Charge Related To Step Up In Cost Basis InventoryChargeRelatedToStepUpInCostBasis	36927000	USD
CY2017	lfus	Inventory Charge Related To Step Up In Cost Basis InventoryChargeRelatedToStepUpInCostBasis	1607000	USD
CY2019	us-gaap	Share Based Compensation ShareBasedCompensation	19046000	USD
CY2018	us-gaap	Share Based Compensation ShareBasedCompensation	27431000	USD
CY2017	us-gaap	Share Based Compensation ShareBasedCompensation	16315000	USD
CY2019	us-gaap	Excess Tax Benefit From Share Based Compensation Operating Activities ExcessTaxBenefitFromShareBasedCompensationOperatingActivities	-4854000	USD
CY2018	us-gaap	Excess Tax Benefit From Share Based Compensation Operating Activities ExcessTaxBenefitFromShareBasedCompensationOperatingActivities	670000	USD
CY2017	us-gaap	Excess Tax Benefit From Share Based Compensation Operating Activities ExcessTaxBenefitFromShareBasedCompensationOperatingActivities	0	USD
CY2019	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-1147000	USD
CY2018	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-4679000	USD
CY2017	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	17063000	USD
CY2019	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	-6638000	USD
CY2018	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	-620000	USD
CY2017	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	-6048000	USD
CY2019	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	-28497000	USD
CY2018	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	3539000	USD
CY2017	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	11087000	USD
CY2019	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	-22094000	USD
CY2018	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	33971000	USD
CY2017	us-gaap	Increase Decrease In Inventories IncreaseDecreaseInInventories	20180000	USD
CY2019	us-gaap	Increase Decrease In Accounts Payable IncreaseDecreaseInAccountsPayable	-22574000	USD
CY2018	us-gaap	Increase Decrease In Accounts Payable IncreaseDecreaseInAccountsPayable	13708000	USD
CY2017	us-gaap	Increase Decrease In Accounts Payable IncreaseDecreaseInAccountsPayable	6494000	USD
CY2019	us-gaap	Increase Decrease In Accrued Liabilities IncreaseDecreaseInAccruedLiabilities	-54242000	USD
CY2018	us-gaap	Increase Decrease In Accrued Liabilities IncreaseDecreaseInAccruedLiabilities	29329000	USD
CY2017	us-gaap	Increase Decrease In Accrued Liabilities IncreaseDecreaseInAccruedLiabilities	50626000	USD
CY2019	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	-10573000	USD
CY2018	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	7269000	USD
CY2017	us-gaap	Increase Decrease In Prepaid Deferred Expense And Other Assets IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets	-19754000	USD
CY2019	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	245328000	USD
CY2018	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	331828000	USD
CY2017	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	269170000	USD
CY2019	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	775000	USD
CY2018	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	318474000	USD
CY2017	us-gaap	Payments To Acquire Businesses Net Of Cash Acquired PaymentsToAcquireBusinessesNetOfCashAcquired	38512000	USD
CY2019	us-gaap	Proceeds From Maturities Prepayments And Calls Of Shortterm Investments ProceedsFromMaturitiesPrepaymentsAndCallsOfShorttermInvestments	0	USD
CY2018	us-gaap	Proceeds From Maturities Prepayments And Calls Of Shortterm Investments ProceedsFromMaturitiesPrepaymentsAndCallsOfShorttermInvestments	1407000	USD
CY2017	us-gaap	Proceeds From Maturities Prepayments And Calls Of Shortterm Investments ProceedsFromMaturitiesPrepaymentsAndCallsOfShorttermInvestments	3739000	USD
CY2019	lfus	Increase Decrease In Entrusted Loan Payable IncreaseDecreaseInEntrustedLoanPayable	0	USD
CY2018	lfus	Increase Decrease In Entrusted Loan Payable IncreaseDecreaseInEntrustedLoanPayable	0	USD
CY2017	lfus	Increase Decrease In Entrusted Loan Payable IncreaseDecreaseInEntrustedLoanPayable	-3599000	USD
CY2019	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	61895000	USD
CY2018	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	74753000	USD
CY2017	us-gaap	Payments To Acquire Property Plant And Equipment PaymentsToAcquirePropertyPlantAndEquipment	65925000	USD
CY2019	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	6213000	USD
CY2018	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	9572000	USD
CY2017	us-gaap	Proceeds From Sale Of Property Plant And Equipment ProceedsFromSaleOfPropertyPlantAndEquipment	962000	USD
CY2019	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-56457000	USD
CY2018	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-382248000	USD
CY2017	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-96137000	USD
CY2019	us-gaap	Proceeds From Long Term Lines Of Credit ProceedsFromLongTermLinesOfCredit	0	USD
CY2018	us-gaap	Proceeds From Long Term Lines Of Credit ProceedsFromLongTermLinesOfCredit	60000000	USD
CY2017	us-gaap	Proceeds From Long Term Lines Of Credit ProceedsFromLongTermLinesOfCredit	15000000	USD
CY2019	us-gaap	Proceeds From Issuance Of Unsecured Debt ProceedsFromIssuanceOfUnsecuredDebt	0	USD
CY2018	us-gaap	Proceeds From Issuance Of Unsecured Debt ProceedsFromIssuanceOfUnsecuredDebt	75000000	USD
CY2017	us-gaap	Proceeds From Issuance Of Unsecured Debt ProceedsFromIssuanceOfUnsecuredDebt	9375000	USD
CY2019	us-gaap	Proceeds From Repayments Of Notes Payable ProceedsFromRepaymentsOfNotesPayable	0	USD
CY2018	us-gaap	Proceeds From Repayments Of Notes Payable ProceedsFromRepaymentsOfNotesPayable	175000000	USD
CY2017	us-gaap	Proceeds From Repayments Of Notes Payable ProceedsFromRepaymentsOfNotesPayable	125000000	USD
CY2019	us-gaap	Repayments Of Unsecured Debt RepaymentsOfUnsecuredDebt	10000000	USD
CY2018	us-gaap	Repayments Of Unsecured Debt RepaymentsOfUnsecuredDebt	42500000	USD
CY2017	us-gaap	Repayments Of Unsecured Debt RepaymentsOfUnsecuredDebt	7188000	USD
CY2019	us-gaap	Repayments Of Long Term Lines Of Credit RepaymentsOfLongTermLinesOfCredit	0	USD
CY2018	us-gaap	Repayments Of Long Term Lines Of Credit RepaymentsOfLongTermLinesOfCredit	60000000	USD
CY2017	us-gaap	Repayments Of Long Term Lines Of Credit RepaymentsOfLongTermLinesOfCredit	127500000	USD
CY2019	lfus	Proceedsfrom Repurchaseof Stock Based Award Activities ProceedsfromRepurchaseofStockBasedAwardActivities	7800000	USD
CY2018	lfus	Proceedsfrom Repurchaseof Stock Based Award Activities ProceedsfromRepurchaseofStockBasedAwardActivities	18857000	USD
CY2017	lfus	Proceedsfrom Repurchaseof Stock Based Award Activities ProceedsfromRepurchaseofStockBasedAwardActivities	-2373000	USD
CY2019	lfus	Paymentsof Entrusted Loan PaymentsofEntrustedLoan	0	USD
CY2018	lfus	Paymentsof Entrusted Loan PaymentsofEntrustedLoan	0	USD
CY2017	lfus	Paymentsof Entrusted Loan PaymentsofEntrustedLoan	3599000	USD
CY2019	us-gaap	Payments Of Dividends PaymentsOfDividends	44689000	USD
CY2018	us-gaap	Payments Of Dividends PaymentsOfDividends	39993000	USD
CY2017	us-gaap	Payments Of Dividends PaymentsOfDividends	31770000	USD
CY2019	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	99387000	USD
CY2018	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	63564000	USD
CY2017	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	0	USD
CY2019	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	0	USD
CY2018	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	-903000	USD
CY2017	us-gaap	Proceeds From Payments For Other Financing Activities ProceedsFromPaymentsForOtherFinancingActivities	-1626000	USD
CY2018	lfus	Effective Income Tax Rate Reconciliation Provisional Tax Act Impact Other Than Toll Charge Amount EffectiveIncomeTaxRateReconciliationProvisionalTaxActImpactOtherThanTollChargeAmount	966000	USD
CY2019	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	-559000	USD
CY2017	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	0	USD
CY2019	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-146276000	USD
CY2018	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	121897000	USD
CY2017	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-24681000	USD
CY2019	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	-1189000	USD
CY2018	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	-11420000	USD
CY2017	us-gaap	Effect Of Exchange Rate On Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents EffectOfExchangeRateOnCashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	6200000	USD
CY2019	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	41406000	USD
CY2018	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	60057000	USD
CY2017	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	154552000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	489733000	USD
CY2017Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	429676000	USD
CY2016Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	275124000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	531139000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	489733000	USD
CY2017Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	429676000	USD
CY2019	us-gaap	Interest Paid Net InterestPaidNet	21240000	USD
CY2018	us-gaap	Interest Paid Net InterestPaidNet	18462000	USD
CY2017	us-gaap	Interest Paid Net InterestPaidNet	10569000	USD
CY2019	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	40518000	USD
CY2018	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	41904000	USD
CY2017	us-gaap	Income Taxes Paid Net IncomeTaxesPaidNet	18088000	USD
CY2019	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	11110000	USD
CY2018	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	0	USD
CY2016Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	814931000	USD
CY2017	us-gaap	Profit Loss ProfitLoss	119519000	USD
CY2017	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	10911000	USD
CY2017	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	16315000	USD
CY2017	us-gaap	Minority Interest Decrease From Distributions To Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders	6000	USD
CY2017	us-gaap	Adjustments Related To Tax Withholding For Share Based Compensation AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation	4784000	USD
CY2017	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	2440000	USD
CY2017	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	31770000	USD
CY2017Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	927556000	USD
CY2018	us-gaap	Profit Loss ProfitLoss	164565000	USD
CY2018	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	-24461000	USD
CY2018	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	27431000	USD
CY2018	us-gaap	Minority Interest Decrease From Distributions To Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders	6000	USD
CY2018	us-gaap	Adjustments Related To Tax Withholding For Share Based Compensation AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation	7252000	USD
CY2018	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	26109000	USD
CY2018	us-gaap	Stock Issued During Period Value New Issues StockIssuedDuringPeriodValueNewIssues	472301000	USD
CY2018Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	87091000	USD
CY2018	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	67908000	USD
CY2018	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	39993000	USD
CY2018Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1478342000	USD
CY2019	us-gaap	Profit Loss ProfitLoss	139082000	USD
CY2019	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	-8899000	USD
CY2019	us-gaap	Adjustments To Additional Paid In Capital Sharebased Compensation Requisite Service Period Recognition Value AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue	19046000	USD
CY2019	us-gaap	Adjustments Related To Tax Withholding For Share Based Compensation AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation	4957000	USD
CY2019	us-gaap	Stock Issued During Period Value Stock Options Exercised StockIssuedDuringPeriodValueStockOptionsExercised	13124000	USD
CY2019	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	95036000	USD
CY2019	us-gaap	Dividends Common Stock Cash DividendsCommonStockCash	44688000	USD
CY2019Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	1496014000	USD
CY2019	us-gaap	Fiscal Period FiscalPeriod	<div style="line-height:120%;text-align:justify;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;font-style:italic;font-weight:bold;">Fiscal Year</span><span style="font-family:inherit;font-size:10pt;font-weight:bold;"> </span></div><div style="line-height:120%;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;">References herein to “2019”, “fiscal 2019” or “fiscal year 2019” refer to the fiscal year ended </span><span style="font-family:inherit;font-size:10pt;">December 28, 2019</span><span style="font-family:inherit;font-size:10pt;">. References herein to “2018”, “fiscal 2018” or “fiscal year 2018” refer to the fiscal year ended </span><span style="font-family:inherit;font-size:10pt;">December 29, 2018</span><span style="font-family:inherit;font-size:10pt;">. References herein to “2017”, “fiscal 2017” or “fiscal year 2017” refer to the fiscal year ended </span><span style="font-family:inherit;font-size:10pt;">December 30, 2017</span><span style="font-family:inherit;font-size:10pt;">. The Company operates on a 52-53 week fiscal year (4-4-5 basis) ending on the Saturday closest to December 31. </span></div>
CY2019	us-gaap	Use Of Estimates UseOfEstimates	<div style="line-height:120%;text-align:justify;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;font-style:italic;font-weight:bold;">Use of Estimates</span><span style="font-family:inherit;font-size:10pt;font-weight:bold;"> </span></div><div style="line-height:120%;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;"> </span></div><div style="line-height:120%;text-align:justify;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;">The process of preparing financial statements in conformity with generally accepted accounting principles in the United States of America requires management to make estimates and assumptions that affect the amounts of assets and liabilities at the date of the Consolidated Financial Statements, and the reported amounts of revenues and expenses and the accompanying notes. The Company evaluates and updates its assumptions and estimates on an ongoing basis and may employ outside experts to assist in its evaluation, as considered necessary. Actual results could differ from those estimates.</span></div>
CY2019	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	600000	USD
CY2018	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	-700000	USD
CY2019Q4	us-gaap	Equity Method Investments EquityMethodInvestments	11100000	USD
CY2018Q4	us-gaap	Equity Method Investments EquityMethodInvestments	11600000	USD
CY2019Q4	us-gaap	Cost Method Investments CostMethodInvestments	400000	USD
CY2018Q4	us-gaap	Cost Method Investments CostMethodInvestments	7900000	USD
CY2019Q4	us-gaap	Cost Method Investments CostMethodInvestments	400000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Expected Amortization Of Prior Service Cost Credit Next Fiscal Year DefinedBenefitPlanExpectedAmortizationOfPriorServiceCostCreditNextFiscalYear	200000	USD
CY2019	us-gaap	Number Of Reporting Units NumberOfReportingUnits	7	unit
CY2019	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	1503873000	USD
CY2018	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	1718468000	USD
CY2019	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	-5200000	USD
CY2018	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	900000	USD
CY2017	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	-2400000	USD
CY2019Q4	us-gaap	Loss Contingency Accrual Carrying Value Noncurrent LossContingencyAccrualCarryingValueNoncurrent	600000	EUR
CY2019Q4	us-gaap	Loss Contingency Accrual Carrying Value Noncurrent LossContingencyAccrualCarryingValueNoncurrent	700000	USD
CY2018Q4	us-gaap	Loss Contingency Accrual Carrying Value Noncurrent LossContingencyAccrualCarryingValueNoncurrent	1100000	EUR
CY2018Q4	us-gaap	Loss Contingency Accrual Carrying Value Noncurrent LossContingencyAccrualCarryingValueNoncurrent	1300000	USD
CY2017Q4	us-gaap	Income Tax Expense Benefit Continuing Operations Adjustment Of Deferred Tax Asset Liability IncomeTaxExpenseBenefitContinuingOperationsAdjustmentOfDeferredTaxAssetLiability	47000000.0	USD
CY2017Q4	lfus	Income Tax Expense Benefit Continuing Operations Adjustment Of Deferred Tax Asset Liability Toll Charge IncomeTaxExpenseBenefitContinuingOperationsAdjustmentOfDeferredTaxAssetLiabilityTollCharge	49000000.0	USD
CY2017Q4	lfus	Income Tax Expense Benefit Continuing Operations Adjustment Of Deferred Tax Asset Liability Other Than Toll Charge IncomeTaxExpenseBenefitContinuingOperationsAdjustmentOfDeferredTaxAssetLiabilityOtherThanTollCharge	2000000.0	USD
CY2018Q4	us-gaap	Tax Cuts And Jobs Act Of2017 Income Tax Expense Benefit TaxCutsAndJobsActOf2017IncomeTaxExpenseBenefit	3200000	USD
CY2019	lfus	Income Tax Expense Benefit Continuing Operations Adjustment Of Deferred Tax Asset Liability Toll Charge Noncurrent IncomeTaxExpenseBenefitContinuingOperationsAdjustmentOfDeferredTaxAssetLiabilityTollChargeNoncurrent	-23800000	USD
CY2019	lfus	Income Tax Expense Benefit Continuing Operations Adjustmentof Deferred Tax Asset Liability Toll Charge Current IncomeTaxExpenseBenefitContinuingOperationsAdjustmentofDeferredTaxAssetLiabilityTollChargeCurrent	-3000000.0	USD
CY2019Q4	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.01
CY2018Q1	us-gaap	Share Price SharePrice	207.5
CY2019	us-gaap	Business Acquisitions Pro Forma Revenue BusinessAcquisitionsProFormaRevenue	1735181000	USD
CY2018	us-gaap	Business Acquisitions Pro Forma Revenue BusinessAcquisitionsProFormaRevenue	1564956000	USD
CY2019	lfus	Business Acquisition Pro Forma Income Lossfrom Continuing Operationsbefore Tax BusinessAcquisitionProFormaIncomeLossfromContinuingOperationsbeforeTax	272724000	USD
CY2018	lfus	Business Acquisition Pro Forma Income Lossfrom Continuing Operationsbefore Tax BusinessAcquisitionProFormaIncomeLossfromContinuingOperationsbeforeTax	142150000	USD
CY2019	us-gaap	Business Acquisitions Pro Forma Net Income Loss BusinessAcquisitionsProFormaNetIncomeLoss	215228000	USD
CY2018	us-gaap	Business Acquisitions Pro Forma Net Income Loss BusinessAcquisitionsProFormaNetIncomeLoss	75604000	USD
CY2019	us-gaap	Business Acquisition Pro Forma Earnings Per Share Basic BusinessAcquisitionProFormaEarningsPerShareBasic	8.61
CY2018	us-gaap	Business Acquisition Pro Forma Earnings Per Share Basic BusinessAcquisitionProFormaEarningsPerShareBasic	3.05
CY2019	us-gaap	Business Acquisition Pro Forma Earnings Per Share Diluted BusinessAcquisitionProFormaEarningsPerShareDiluted	8.53
CY2018	us-gaap	Business Acquisition Pro Forma Earnings Per Share Diluted BusinessAcquisitionProFormaEarningsPerShareDiluted	3.00
CY2019	lfus	Inventory Amortization Period InventoryAmortizationPeriod	P5M
CY2019Q4	us-gaap	Inventory Raw Materials Net Of Reserves InventoryRawMaterialsNetOfReserves	76732000	USD
CY2018Q4	us-gaap	Inventory Raw Materials Net Of Reserves InventoryRawMaterialsNetOfReserves	76060000	USD
CY2019Q4	us-gaap	Inventory Work In Process Net Of Reserves InventoryWorkInProcessNetOfReserves	84561000	USD
CY2018Q4	us-gaap	Inventory Work In Process Net Of Reserves InventoryWorkInProcessNetOfReserves	97645000	USD
CY2019Q4	us-gaap	Inventory Finished Goods Net Of Reserves InventoryFinishedGoodsNetOfReserves	110388000	USD
CY2018Q4	us-gaap	Inventory Finished Goods Net Of Reserves InventoryFinishedGoodsNetOfReserves	117207000	USD
CY2019Q4	us-gaap	Other Inventory Net Of Reserves OtherInventoryNetOfReserves	34174000	USD
CY2018Q4	us-gaap	Other Inventory Net Of Reserves OtherInventoryNetOfReserves	32684000	USD
CY2019Q4	us-gaap	Inventory Net InventoryNet	237507000	USD
CY2018Q4	us-gaap	Inventory Net InventoryNet	258228000	USD
CY2019Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	419915000	USD
CY2018Q4	us-gaap	Accumulated Depreciation Depletion And Amortization Property Plant And Equipment AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment	383415000	USD
CY2019Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	344617000	USD
CY2018Q4	us-gaap	Property Plant And Equipment Net PropertyPlantAndEquipmentNet	339894000	USD
CY2019	us-gaap	Depreciation Depreciation	52500000	USD
CY2018	us-gaap	Depreciation Depreciation	51000000.0	USD
CY2017	us-gaap	Depreciation Depreciation	38300000	USD
CY2017Q4	us-gaap	Goodwill Goodwill	453414000	USD
CY2018	us-gaap	Goodwill Acquired During Period GoodwillAcquiredDuringPeriod	382903000	USD
CY2018	us-gaap	Goodwill Foreign Currency Translation Gain Loss GoodwillForeignCurrencyTranslationGainLoss	-9602000	USD
CY2018Q4	us-gaap	Goodwill Goodwill	826715000	USD
CY2019	us-gaap	Goodwill Foreign Currency Translation Gain Loss GoodwillForeignCurrencyTranslationGainLoss	-6126000	USD
CY2019Q4	us-gaap	Goodwill Goodwill	820589000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Four FiniteLivedIntangibleAssetsAmortizationExpenseYearFour	32372000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	544586000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	223339000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	321247000	USD
CY2018Q4	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	557535000	USD
CY2018Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	196061000	USD
CY2018Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	361474000	USD
CY2018	us-gaap	Finitelived Intangible Assets Acquired1 FinitelivedIntangibleAssetsAcquired1	212700000	USD
CY2019	us-gaap	Finitelived Intangible Assets Acquired1 FinitelivedIntangibleAssetsAcquired1	212720000	USD
CY2019	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	40000000.0	USD
CY2018	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	52200000	USD
CY2017	us-gaap	Amortization Of Intangible Assets AmortizationOfIntangibleAssets	24700000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Remainder Of Fiscal Year FiniteLivedIntangibleAssetsAmortizationExpenseRemainderOfFiscalYear	39660000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Two FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo	37865000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Three FiniteLivedIntangibleAssetsAmortizationExpenseYearThree	36724000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense Year Five FiniteLivedIntangibleAssetsAmortizationExpenseYearFive	29273000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Amortization Expense After Year Five FiniteLivedIntangibleAssetsAmortizationExpenseAfterYearFive	145353000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	321247000	USD
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Authorized ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized	1200000	shares
CY2019Q4	us-gaap	Employee Related Liabilities Current EmployeeRelatedLiabilitiesCurrent	40774000	USD
CY2018Q4	us-gaap	Employee Related Liabilities Current EmployeeRelatedLiabilitiesCurrent	60640000	USD
CY2019Q4	us-gaap	Operating Lease Liability Current OperatingLeaseLiabilityCurrent	7259000	USD
CY2019Q4	us-gaap	Interest And Dividends Payable Current InterestAndDividendsPayableCurrent	5058000	USD
CY2018Q4	us-gaap	Interest And Dividends Payable Current InterestAndDividendsPayableCurrent	5137000	USD
CY2019Q4	us-gaap	Accrued Professional Fees Current AccruedProfessionalFeesCurrent	3986000	USD
CY2018Q4	us-gaap	Accrued Professional Fees Current AccruedProfessionalFeesCurrent	6169000	USD
CY2019Q4	us-gaap	Restructuring Reserve Current RestructuringReserveCurrent	2679000	USD
CY2018Q4	us-gaap	Restructuring Reserve Current RestructuringReserveCurrent	3887000	USD
CY2019Q4	us-gaap	Accrual For Taxes Other Than Income Taxes Current AccrualForTaxesOtherThanIncomeTaxesCurrent	1940000	USD
CY2018Q4	us-gaap	Accrual For Taxes Other Than Income Taxes Current AccrualForTaxesOtherThanIncomeTaxesCurrent	21523000	USD
CY2019Q4	lfus	Accrued Share Repurchases Current AccruedShareRepurchasesCurrent	0	USD
CY2018Q4	lfus	Accrued Share Repurchases Current AccruedShareRepurchasesCurrent	4349000	USD
CY2019Q4	us-gaap	Other Accrued Liabilities Current OtherAccruedLiabilitiesCurrent	22424000	USD
CY2018Q4	us-gaap	Other Accrued Liabilities Current OtherAccruedLiabilitiesCurrent	36700000	USD
CY2019Q4	us-gaap	Accrued Liabilities Current AccruedLiabilitiesCurrent	84120000	USD
CY2018Q4	us-gaap	Accrued Liabilities Current AccruedLiabilitiesCurrent	138405000	USD
CY2019Q4	us-gaap	Operating Lease Right Of Use Asset OperatingLeaseRightOfUseAsset	21918000	USD
CY2019Q4	us-gaap	Operating Lease Liability Current OperatingLeaseLiabilityCurrent	7259000	USD
CY2019Q4	us-gaap	Operating Lease Liability Noncurrent OperatingLeaseLiabilityNoncurrent	17166000	USD
CY2019Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	24425000	USD
CY2019	us-gaap	Short Term Lease Cost ShortTermLeaseCost	562000	USD
CY2019	us-gaap	Variable Lease Cost VariableLeaseCost	916000	USD
CY2019	us-gaap	Operating Lease Cost OperatingLeaseCost	8664000	USD
CY2019	us-gaap	Operating Lease Expense OperatingLeaseExpense	10142000	USD
CY2019	us-gaap	Operating Lease Expense OperatingLeaseExpense	10100000	USD
CY2018	us-gaap	Lease And Rental Expense LeaseAndRentalExpense	9600000	USD
CY2018Q4	us-gaap	Operating Leases Future Minimum Payments Due In Five Years OperatingLeasesFutureMinimumPaymentsDueInFiveYears	2946000	USD
CY2018Q4	us-gaap	Operating Leases Future Minimum Payments Due Thereafter OperatingLeasesFutureMinimumPaymentsDueThereafter	2774000	USD
CY2017	us-gaap	Lease And Rental Expense LeaseAndRentalExpense	11600000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Liability Payments Due Next Twelve Months LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths	8207000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	6383000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	5297000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	3518000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	3165000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Liability Payments Due After Year Five LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive	458000	USD
CY2019Q4	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	27028000	USD
CY2019Q4	us-gaap	Operating Lease Liability OperatingLeaseLiability	24425000	USD
CY2019Q4	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P4Y18D
CY2019Q4	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.0511
CY2019	us-gaap	Operating Lease Payments OperatingLeasePayments	8936000	USD
CY2019	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	3962000	USD
CY2018Q4	us-gaap	Operating Leases Future Minimum Payments Due Current OperatingLeasesFutureMinimumPaymentsDueCurrent	9133000	USD
CY2018Q4	us-gaap	Operating Leases Future Minimum Payments Due In Two Years OperatingLeasesFutureMinimumPaymentsDueInTwoYears	7590000	USD
CY2018Q4	us-gaap	Operating Leases Future Minimum Payments Due In Three Years OperatingLeasesFutureMinimumPaymentsDueInThreeYears	5574000	USD
CY2018Q4	us-gaap	Operating Leases Future Minimum Payments Due In Four Years OperatingLeasesFutureMinimumPaymentsDueInFourYears	4590000	USD
CY2019Q4	us-gaap	Deferred Finance Costs Net DeferredFinanceCostsNet	3669000	USD
CY2019Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	669158000	USD
CY2018Q4	us-gaap	Operating Leases Future Minimum Payments Due OperatingLeasesFutureMinimumPaymentsDue	32607000	USD
CY2019	us-gaap	Restructuring Charges RestructuringCharges	12711000	USD
CY2019	us-gaap	Asset Impairment Charges AssetImpairmentCharges	322000	USD
CY2019	us-gaap	Restructuring Costs And Asset Impairment Charges RestructuringCostsAndAssetImpairmentCharges	13033000	USD
CY2018	us-gaap	Restructuring Charges RestructuringCharges	10365000	USD
CY2018	us-gaap	Asset Impairment Charges AssetImpairmentCharges	2218000	USD
CY2018	us-gaap	Restructuring Costs And Asset Impairment Charges RestructuringCostsAndAssetImpairmentCharges	12583000	USD
CY2017	us-gaap	Restructuring Charges RestructuringCharges	2227000	USD
CY2019	us-gaap	Restructuring Charges RestructuringCharges	12700000	USD
CY2018	us-gaap	Restructuring Charges RestructuringCharges	10400000	USD
CY2017	us-gaap	Restructuring Charges RestructuringCharges	2200000	USD
CY2019Q4	us-gaap	Restructuring Reserve RestructuringReserve	2700000	USD
CY2018Q4	us-gaap	Restructuring Reserve RestructuringReserve	3900000	USD
CY2018Q4	us-gaap	Deferred Finance Costs Net DeferredFinanceCostsNet	4636000	USD
CY2019Q4	us-gaap	Long Term Debt LongTermDebt	679158000	USD
CY2018Q4	us-gaap	Long Term Debt LongTermDebt	694730000	USD
CY2019Q4	us-gaap	Long Term Debt Current LongTermDebtCurrent	10000000	USD
CY2018Q4	us-gaap	Long Term Debt Current LongTermDebtCurrent	10000000	USD
CY2018Q4	us-gaap	Long Term Debt Noncurrent LongTermDebtNoncurrent	684730000	USD
CY2019Q4	lfus	Numberof Series NumberofSeries	2	series
CY2019Q4	lfus	Numberof Series NumberofSeries	2	series
CY2019Q4	lfus	Numberof Series NumberofSeries	2	series
CY2018	us-gaap	Interest Paid InterestPaid	18500000	USD
CY2017	us-gaap	Interest Paid InterestPaid	10600000	USD
CY2018Q4	us-gaap	Defined Benefit Plan Amounts Recognized In Balance Sheet DefinedBenefitPlanAmountsRecognizedInBalanceSheet	-32157000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Accumulated Other Comprehensive Income Net Gains Losses Before Tax DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax	-15635000	USD
CY2019Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Next Twelve Months LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths	10000000	USD
CY2019Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Two LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo	10000000	USD
CY2019Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Three LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree	152619000	USD
CY2019Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Four LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour	129808000	USD
CY2019Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Five LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive	0	USD
CY2019Q4	us-gaap	Long Term Debt Maturities Repayments Of Principal After Year Five LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive	380400000	USD
CY2019Q4	us-gaap	Debt Instrument Carrying Amount DebtInstrumentCarryingAmount	682827000	USD
CY2019Q4	us-gaap	Derivative Notional Amount DerivativeNotionalAmount	16000000.0	USD
CY2019Q4	us-gaap	Cash And Cash Equivalents Fair Value Disclosure CashAndCashEquivalentsFairValueDisclosure	118999000	USD
CY2019Q4	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	12969000	USD
CY2019Q4	us-gaap	Trading Securities Debt TradingSecuritiesDebt	10464000	USD
CY2018Q4	us-gaap	Equity Securities Fv Ni EquitySecuritiesFvNi	10312000	USD
CY2018Q4	us-gaap	Trading Securities Debt TradingSecuritiesDebt	9112000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Assets For Plan Benefits Noncurrent DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent	885000	USD
CY2018Q4	us-gaap	Defined Benefit Plan Assets For Plan Benefits Noncurrent DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent	811000	USD
CY2019Q4	us-gaap	Pension And Other Postretirement Defined Benefit Plans Current Liabilities PensionAndOtherPostretirementDefinedBenefitPlansCurrentLiabilities	1106000	USD
CY2018Q4	us-gaap	Pension And Other Postretirement Defined Benefit Plans Current Liabilities PensionAndOtherPostretirementDefinedBenefitPlansCurrentLiabilities	1094000	USD
CY2019Q4	us-gaap	Pension And Other Postretirement Defined Benefit Plans Liabilities Noncurrent PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent	38198000	USD
CY2018Q4	us-gaap	Pension And Other Postretirement Defined Benefit Plans Liabilities Noncurrent PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent	31874000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Amounts Recognized In Balance Sheet DefinedBenefitPlanAmountsRecognizedInBalanceSheet	-38419000	USD
CY2018Q4	us-gaap	Defined Benefit Plan Accumulated Other Comprehensive Income Net Gains Losses Before Tax DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax	-9777000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Accumulated Other Comprehensive Income Net Prior Service Cost Credit Before Tax DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax	4273000	USD
CY2018Q4	us-gaap	Defined Benefit Plan Accumulated Other Comprehensive Income Net Prior Service Cost Credit Before Tax DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax	1607000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Accumulated Other Comprehensive Income Before Tax DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax	19908000	USD
CY2018Q4	us-gaap	Defined Benefit Plan Accumulated Other Comprehensive Income Before Tax DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeBeforeTax	11384000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Expected Amortization Next Fiscal Year DefinedBenefitPlanExpectedAmortizationNextFiscalYear	400000	USD
CY2017	us-gaap	Defined Benefit Plan Interest Cost DefinedBenefitPlanInterestCost	1887000	USD
CY2019	us-gaap	Defined Benefit Plan Expected Return On Plan Assets DefinedBenefitPlanExpectedReturnOnPlanAssets	3187000	USD
CY2018	us-gaap	Defined Benefit Plan Expected Return On Plan Assets DefinedBenefitPlanExpectedReturnOnPlanAssets	3222000	USD
CY2017	us-gaap	Defined Benefit Plan Expected Return On Plan Assets DefinedBenefitPlanExpectedReturnOnPlanAssets	1990000	USD
CY2019	us-gaap	Defined Benefit Plan Interest Cost DefinedBenefitPlanInterestCost	3169000	USD
CY2018	us-gaap	Defined Benefit Plan Interest Cost DefinedBenefitPlanInterestCost	3104000	USD
CY2019	us-gaap	Defined Benefit Plan Amortization Of Prior Service Cost Credit DefinedBenefitPlanAmortizationOfPriorServiceCostCredit	80000	USD
CY2019	lfus	Defined Benefit Plan Amortizationof Net Actuarial Cost DefinedBenefitPlanAmortizationofNetActuarialCost	163000	USD
CY2019	us-gaap	Other Comprehensive Income Defined Benefit Plan Net Prior Service Cost Credit Arising During Period Before Tax OtherComprehensiveIncomeDefinedBenefitPlanNetPriorServiceCostCreditArisingDuringPeriodBeforeTax	-2645000	USD
CY2019	us-gaap	Defined Benefit Plan Actuarial Gain Loss Immediate Recognition As Component In Net Periodic Benefit Cost Credit DefinedBenefitPlanActuarialGainLossImmediateRecognitionAsComponentInNetPeriodicBenefitCostCredit	6251000	USD
CY2019	us-gaap	Defined Benefit Plan Recognized Net Gain Loss Due To Settlements And Curtailments1 DefinedBenefitPlanRecognizedNetGainLossDueToSettlementsAndCurtailments1	-260000	USD
CY2019	lfus	Defined Benefit Plan Foreign Currency Adjustments Immediate Recognitionas Componentin Net Periodic Benefit Cost Credit DefinedBenefitPlanForeignCurrencyAdjustmentsImmediateRecognitionasComponentinNetPeriodicBenefitCostCredit	-131000	USD
CY2019	lfus	Defined Benefit Plan Immediate Recognitionas Componentin Net Periodic Benefit Cost Credit DefinedBenefitPlanImmediateRecognitionasComponentinNetPeriodicBenefitCostCredit	-8524000	USD
CY2019	us-gaap	Defined Benefit Plan Service Cost DefinedBenefitPlanServiceCost	2040000	USD
CY2018	us-gaap	Defined Benefit Plan Service Cost DefinedBenefitPlanServiceCost	2266000	USD
CY2017	us-gaap	Defined Benefit Plan Service Cost DefinedBenefitPlanServiceCost	2037000	USD
CY2019	us-gaap	Defined Benefit Plan Amortization Of Gains Losses DefinedBenefitPlanAmortizationOfGainsLosses	-243000	USD
CY2018	us-gaap	Defined Benefit Plan Amortization Of Gains Losses DefinedBenefitPlanAmortizationOfGainsLosses	-291000	USD
CY2017	us-gaap	Defined Benefit Plan Amortization Of Gains Losses DefinedBenefitPlanAmortizationOfGainsLosses	-337000	USD
CY2019	us-gaap	Defined Benefit Plan Net Periodic Benefit Cost DefinedBenefitPlanNetPeriodicBenefitCost	2265000	USD
CY2018	us-gaap	Defined Benefit Plan Net Periodic Benefit Cost DefinedBenefitPlanNetPeriodicBenefitCost	2439000	USD
CY2017	us-gaap	Defined Benefit Plan Net Periodic Benefit Cost DefinedBenefitPlanNetPeriodicBenefitCost	2271000	USD
CY2019	us-gaap	Defined Benefit Plan Recognized Net Gain Loss Due To Settlements And Curtailments1 DefinedBenefitPlanRecognizedNetGainLossDueToSettlementsAndCurtailments1	-260000	USD
CY2018	us-gaap	Defined Benefit Plan Recognized Net Gain Loss Due To Settlements And Curtailments1 DefinedBenefitPlanRecognizedNetGainLossDueToSettlementsAndCurtailments1	-238000	USD
CY2017	us-gaap	Defined Benefit Plan Recognized Net Gain Loss Due To Settlements And Curtailments1 DefinedBenefitPlanRecognizedNetGainLossDueToSettlementsAndCurtailments1	25000	USD
CY2019	us-gaap	Pension Expense PensionExpense	2525000	USD
CY2018	us-gaap	Pension Expense PensionExpense	2677000	USD
CY2017	us-gaap	Pension Expense PensionExpense	2246000	USD
CY2019	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Discount Rate DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate	0.031
CY2018	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Discount Rate DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate	0.028
CY2017	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Discount Rate DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostDiscountRate	0.030
CY2019	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Expected Long Term Return On Assets DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets	0.045
CY2018	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Expected Long Term Return On Assets DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets	0.042
CY2017	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Expected Long Term Return On Assets DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets	0.045
CY2019	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Rate Of Compensation Increase DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease	0.046
CY2018	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Rate Of Compensation Increase DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease	0.050
CY2017	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Rate Of Compensation Increase DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostRateOfCompensationIncrease	0.045
CY2019Q4	us-gaap	Defined Benefit Plan Pension Plan With Projected Benefit Obligation In Excess Of Plan Assets Projected Benefit Obligation DefinedBenefitPlanPensionPlanWithProjectedBenefitObligationInExcessOfPlanAssetsProjectedBenefitObligation	81362000	USD
CY2018Q4	us-gaap	Defined Benefit Plan Pension Plan With Projected Benefit Obligation In Excess Of Plan Assets Projected Benefit Obligation DefinedBenefitPlanPensionPlanWithProjectedBenefitObligationInExcessOfPlanAssetsProjectedBenefitObligation	70579000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Pension Plan With Projected Benefit Obligation In Excess Of Plan Assets Plan Assets DefinedBenefitPlanPensionPlanWithProjectedBenefitObligationInExcessOfPlanAssetsPlanAssets	42058000	USD
CY2018Q4	us-gaap	Defined Benefit Plan Pension Plan With Projected Benefit Obligation In Excess Of Plan Assets Plan Assets DefinedBenefitPlanPensionPlanWithProjectedBenefitObligationInExcessOfPlanAssetsPlanAssets	37611000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Pension Plans With Accumulated Benefit Obligations In Excess Of Plan Assets Aggregate Accumulated Benefit Obligation DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation	75744000	USD
CY2018Q4	us-gaap	Defined Benefit Plan Pension Plans With Accumulated Benefit Obligations In Excess Of Plan Assets Aggregate Accumulated Benefit Obligation DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateAccumulatedBenefitObligation	66049000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Pension Plans With Accumulated Benefit Obligations In Excess Of Plan Assets Aggregate Fair Value Of Plan Assets DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateFairValueOfPlanAssets	42058000	USD
CY2018Q4	us-gaap	Defined Benefit Plan Pension Plans With Accumulated Benefit Obligations In Excess Of Plan Assets Aggregate Fair Value Of Plan Assets DefinedBenefitPlanPensionPlansWithAccumulatedBenefitObligationsInExcessOfPlanAssetsAggregateFairValueOfPlanAssets	36003000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Discount Rate DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate	0.023
CY2018Q4	us-gaap	Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Discount Rate DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate	0.031
CY2017Q4	us-gaap	Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Discount Rate DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate	0.031
CY2019Q4	us-gaap	Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Rate Of Compensation Increase DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease	0.047
CY2018Q4	us-gaap	Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Rate Of Compensation Increase DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease	0.046
CY2017Q4	us-gaap	Defined Benefit Plan Assumptions Used Calculating Benefit Obligation Rate Of Compensation Increase DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationRateOfCompensationIncrease	0.050
CY2019Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Next Twelve Months DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths	4511000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Year Two DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo	4726000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Year Three DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree	4624000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Year Four DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour	4900000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Year Five DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive	4910000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Expected Future Benefit Payments Five Fiscal Years Thereafter DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter	29364000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Expected Future Employer Contributions Next Fiscal Year DefinedBenefitPlanExpectedFutureEmployerContributionsNextFiscalYear	2300000	USD
CY2019	us-gaap	Pension And Other Postretirement Benefit Expense PensionAndOtherPostretirementBenefitExpense	1400000	USD
CY2018	us-gaap	Pension And Other Postretirement Benefit Expense PensionAndOtherPostretirementBenefitExpense	1800000	USD
CY2017	us-gaap	Pension And Other Postretirement Benefit Expense PensionAndOtherPostretirementBenefitExpense	1100000	USD
CY2019Q4	us-gaap	Defined Benefit Plan Benefit Obligation DefinedBenefitPlanBenefitObligation	2800000	USD
CY2018Q4	us-gaap	Defined Benefit Plan Benefit Obligation DefinedBenefitPlanBenefitObligation	2700000	USD
CY2019	us-gaap	Amount Recognized In Net Periodic Benefit Cost And Other Comprehensive Income Loss Before Tax AmountRecognizedInNetPeriodicBenefitCostAndOtherComprehensiveIncomeLossBeforeTax	600000	USD
CY2019	us-gaap	Defined Benefit Plan Assumptions Used Calculating Net Periodic Benefit Cost Expected Long Term Return On Assets DefinedBenefitPlanAssumptionsUsedCalculatingNetPeriodicBenefitCostExpectedLongTermReturnOnAssets	0.045
CY2019Q4	us-gaap	Defined Benefit Plan Weighted Average Asset Allocations DefinedBenefitPlanWeightedAverageAssetAllocations	1
CY2018Q4	us-gaap	Defined Benefit Plan Weighted Average Asset Allocations DefinedBenefitPlanWeightedAverageAssetAllocations	1
CY2019Q4	us-gaap	Defined Benefit Plan Fair Value Of Plan Assets DefinedBenefitPlanFairValueOfPlanAssets	78502000	USD
CY2018Q4	us-gaap	Defined Benefit Plan Fair Value Of Plan Assets DefinedBenefitPlanFairValueOfPlanAssets	70676000	USD
CY2019	lfus	Sharebased Compensation Arrangementby Sharebased Payment Award Options Convertedin Period SharebasedCompensationArrangementbySharebasedPaymentAwardOptionsConvertedinPeriod	499027	shares
CY2019	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	3300000	USD
CY2019	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized Period For Recognition1 EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1	P1Y9M18D
CY2019	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	19900000	USD
CY2018	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	28200000	USD
CY2017	us-gaap	Allocated Share Based Compensation Expense AllocatedShareBasedCompensationExpense	17300000	USD
CY2018Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	669356	shares
CY2018Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	116.29
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Gross ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross	76742	shares
CY2019	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Grants In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice	199.24
CY2019	us-gaap	Stock Issued During Period Shares Stock Options Exercised StockIssuedDuringPeriodSharesStockOptionsExercised	134982	shares
CY2019	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Exercises In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice	97.22
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Forfeitures In Period ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod	10651	shares
CY2019	us-gaap	Share Based Compensation Arrangements By Share Based Payment Award Options Forfeitures In Period Weighted Average Exercise Price ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice	108.23
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber	600465	shares
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice	131.32
CY2019	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Outstanding Weighted Average Remaining Contractual Term2 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2	P4Y7M6D
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue	37048000	USD
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Number ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber	413109	shares
CY2019Q4	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercisable Weighted Average Exercise Price ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice	111.65
CY2019	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Weighted Average Remaining Contractual Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1	P4Y
CY2019Q4	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Exercisable Intrinsic Value1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1	33215000	USD
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	12500000	USD
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	38300000	USD
CY2017	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Exercises In Period Total Intrinsic Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue	2200000	USD
CY2019	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Vested In Period Fair Value1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1	15500000	USD
CY2018	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Vested In Period Fair Value1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1	20800000	USD
CY2017	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Options Vested In Period Fair Value1 SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1	15000000.0	USD
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Share Based Liabilities Paid ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsShareBasedLiabilitiesPaid	900000	USD
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Share Based Liabilities Paid ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsShareBasedLiabilitiesPaid	1100000	USD
CY2017	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Share Based Liabilities Paid ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsShareBasedLiabilitiesPaid	900000	USD
CY2019Q4	us-gaap	Employee Service Share Based Compensation Nonvested Awards Total Compensation Cost Not Yet Recognized EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized	17400000	USD
CY2018	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	391972	shares
CY2019	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Fair Value Assumptions Expected Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1	P4Y4M24D
CY2018	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	67900000	USD
CY2019	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	95000000.0	USD
CY2018	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	6000000.0	USD
CY2017	us-gaap	Employee Service Share Based Compensation Tax Benefit From Compensation Expense EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense	6000000.0	USD
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue	47.63
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue	45.19
CY2017	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Options Grants In Period Weighted Average Grant Date Fair Value ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue	30.77
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Risk Free Interest Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate	0.0233
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Risk Free Interest Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate	0.0279
CY2017	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Risk Free Interest Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate	0.0179
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Dividend Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate	0.0086
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Dividend Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate	0.0077
CY2017	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Dividend Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate	0.0086
CY2019	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Volatility Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate	0.270
CY2018	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Volatility Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate	0.250
CY2017	us-gaap	Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Volatility Rate ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate	0.230
CY2018	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Fair Value Assumptions Expected Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1	P4Y4M24D
CY2017	us-gaap	Sharebased Compensation Arrangement By Sharebased Payment Award Fair Value Assumptions Expected Term1 SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1	P4Y4M24D
CY2018Q2	us-gaap	Stock Repurchase Program Number Of Shares Authorized To Be Repurchased StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased	1000000	shares
CY2019Q2	us-gaap	Stock Repurchase Program Number Of Shares Authorized To Be Repurchased StockRepurchaseProgramNumberOfSharesAuthorizedToBeRepurchased	1000000	shares
CY2019	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	579916	shares
CY2019	us-gaap	Other Comprehensive Income Loss Before Tax OtherComprehensiveIncomeLossBeforeTax	-10625000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Tax OtherComprehensiveIncomeLossTax	-1726000	USD
CY2019	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-8899000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Before Tax OtherComprehensiveIncomeLossBeforeTax	-24414000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Tax OtherComprehensiveIncomeLossTax	47000	USD
CY2018	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-24461000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Before Tax OtherComprehensiveIncomeLossBeforeTax	11296000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Tax OtherComprehensiveIncomeLossTax	385000	USD
CY2017	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	10911000	USD
CY2019	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	834000	USD
CY2018	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	119000	USD
CY2017	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	224533000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	165884000	USD
CY2018	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	204942000	USD
CY2017	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	204037000	USD
CY2019	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	-3495000	USD
CY2018	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	-3193000	USD
CY2017	us-gaap	Current Federal Tax Expense Benefit CurrentFederalTaxExpenseBenefit	34060000	USD
CY2017Q4	us-gaap	Income Tax Expense Benefit Continuing Operations Adjustment Of Deferred Tax Asset Liability IncomeTaxExpenseBenefitContinuingOperationsAdjustmentOfDeferredTaxAssetLiability	47000000.0	USD
CY2017Q4	lfus	Income Tax Expense Benefit Continuing Operations Adjustment Of Deferred Tax Asset Liability Toll Charge IncomeTaxExpenseBenefitContinuingOperationsAdjustmentOfDeferredTaxAssetLiabilityTollCharge	49000000.0	USD
CY2017Q4	lfus	Income Tax Expense Benefit Continuing Operations Adjustment Of Deferred Tax Asset Liability Other Than Toll Charge IncomeTaxExpenseBenefitContinuingOperationsAdjustmentOfDeferredTaxAssetLiabilityOtherThanTollCharge	2000000.0	USD
CY2018Q4	us-gaap	Tax Cuts And Jobs Act Of2017 Income Tax Expense Benefit TaxCutsAndJobsActOf2017IncomeTaxExpenseBenefit	3200000	USD
CY2019	lfus	Income Tax Expense Benefit Continuing Operations Adjustment Of Deferred Tax Asset Liability Toll Charge Noncurrent IncomeTaxExpenseBenefitContinuingOperationsAdjustmentOfDeferredTaxAssetLiabilityTollChargeNoncurrent	-23800000	USD
CY2019	lfus	Income Tax Expense Benefit Continuing Operations Adjustmentof Deferred Tax Asset Liability Toll Charge Current IncomeTaxExpenseBenefitContinuingOperationsAdjustmentofDeferredTaxAssetLiabilityTollChargeCurrent	-3000000.0	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	-11970000	USD
CY2018	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	-49995000	USD
CY2017	us-gaap	Income Loss From Continuing Operations Before Income Taxes Domestic IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic	-20496000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	177854000	USD
CY2018	us-gaap	Income Loss From Continuing Operations Before Income Taxes Foreign IncomeLossFromContinuingOperationsBeforeIncomeTaxesForeign	254937000	USD
CY2017	us-gaap	Current State And Local Tax Expense Benefit CurrentStateAndLocalTaxExpenseBenefit	450000	USD
CY2019	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	30610000	USD
CY2018	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	48130000	USD
CY2017	us-gaap	Current Foreign Tax Expense Benefit CurrentForeignTaxExpenseBenefit	32945000	USD
CY2019	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	27949000	USD
CY2018	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	45056000	USD
CY2017	us-gaap	Current Income Tax Expense Benefit CurrentIncomeTaxExpenseBenefit	67455000	USD
CY2019	us-gaap	Deferred Federal State And Local Tax Expense Benefit DeferredFederalStateAndLocalTaxExpenseBenefit	1839000	USD
CY2018	us-gaap	Deferred Federal State And Local Tax Expense Benefit DeferredFederalStateAndLocalTaxExpenseBenefit	-3896000	USD
CY2017	us-gaap	Deferred Federal State And Local Tax Expense Benefit DeferredFederalStateAndLocalTaxExpenseBenefit	16562000	USD
CY2019	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	-2986000	USD
CY2018	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	-783000	USD
CY2017	us-gaap	Deferred Foreign Income Tax Expense Benefit DeferredForeignIncomeTaxExpenseBenefit	501000	USD
CY2019	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-1147000	USD
CY2018	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	-4679000	USD
CY2017	us-gaap	Deferred Income Tax Expense Benefit DeferredIncomeTaxExpenseBenefit	17063000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	26802000	USD
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	40377000	USD
CY2017	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	84518000	USD
CY2019	us-gaap	Unrecognized Tax Benefits Period Increase Decrease UnrecognizedTaxBenefitsPeriodIncreaseDecrease	3300000	USD
CY2017	lfus	Income Tax Expense Benefit Continuing Operations Adjustment Of Deferred Tax Asset Liability Toll Charge IncomeTaxExpenseBenefitContinuingOperationsAdjustmentOfDeferredTaxAssetLiabilityTollCharge	49000000	USD
CY2017	us-gaap	Income Tax Reconciliation Tax Credits Foreign IncomeTaxReconciliationTaxCreditsForeign	13000000.0	USD
CY2019	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	34836000	USD
CY2018	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	43038000	USD
CY2017	us-gaap	Income Tax Reconciliation Income Tax Expense Benefit At Federal Statutory Income Tax Rate IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate	71413000	USD
CY2019	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	-22457000	USD
CY2018	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	-20472000	USD
CY2017	us-gaap	Income Tax Reconciliation Foreign Income Tax Rate Differential IncomeTaxReconciliationForeignIncomeTaxRateDifferential	-47077000	USD
CY2019	us-gaap	Income Tax Reconciliation Nondeductible Expense Restructuring Charges IncomeTaxReconciliationNondeductibleExpenseRestructuringCharges	6570000	USD
CY2018	us-gaap	Income Tax Reconciliation Nondeductible Expense Restructuring Charges IncomeTaxReconciliationNondeductibleExpenseRestructuringCharges	3107000	USD
CY2017	us-gaap	Income Tax Reconciliation Nondeductible Expense Restructuring Charges IncomeTaxReconciliationNondeductibleExpenseRestructuringCharges	0	USD
CY2019	lfus	Effective Income Tax Rate Reconciliation Impactof Tax Provisions Amount EffectiveIncomeTaxRateReconciliationImpactofTaxProvisionsAmount	6469000	USD
CY2018	lfus	Effective Income Tax Rate Reconciliation Impactof Tax Provisions Amount EffectiveIncomeTaxRateReconciliationImpactofTaxProvisionsAmount	5075000	USD
CY2017	lfus	Effective Income Tax Rate Reconciliation Impactof Tax Provisions Amount EffectiveIncomeTaxRateReconciliationImpactofTaxProvisionsAmount	0	USD
CY2019	lfus	Effective Income Tax Rate Reconciliation Undistributed Foreign Earnings EffectiveIncomeTaxRateReconciliationUndistributedForeignEarnings	2136000	USD
CY2018	lfus	Effective Income Tax Rate Reconciliation Undistributed Foreign Earnings EffectiveIncomeTaxRateReconciliationUndistributedForeignEarnings	4660000	USD
CY2017	lfus	Effective Income Tax Rate Reconciliation Undistributed Foreign Earnings EffectiveIncomeTaxRateReconciliationUndistributedForeignEarnings	12202000	USD
CY2019	lfus	Effective Income Tax Rate Reconciliation Changein Unrecognized Tax Benefitsand Related Accrued Interest EffectiveIncomeTaxRateReconciliationChangeinUnrecognizedTaxBenefitsandRelatedAccruedInterest	-1468000	USD
CY2018	lfus	Effective Income Tax Rate Reconciliation Changein Unrecognized Tax Benefitsand Related Accrued Interest EffectiveIncomeTaxRateReconciliationChangeinUnrecognizedTaxBenefitsandRelatedAccruedInterest	208000	USD
CY2017	lfus	Effective Income Tax Rate Reconciliation Changein Unrecognized Tax Benefitsand Related Accrued Interest EffectiveIncomeTaxRateReconciliationChangeinUnrecognizedTaxBenefitsandRelatedAccruedInterest	914000	USD
CY2019	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	1080000	USD
CY2018	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	-1238000	USD
CY2017	us-gaap	Income Tax Reconciliation State And Local Income Taxes IncomeTaxReconciliationStateAndLocalIncomeTaxes	292000	USD
CY2019	lfus	Income Tax Reconciliation Nondeductible Expense Professional Fees IncomeTaxReconciliationNondeductibleExpenseProfessionalFees	195000	USD
CY2018	lfus	Income Tax Reconciliation Nondeductible Expense Professional Fees IncomeTaxReconciliationNondeductibleExpenseProfessionalFees	1001000	USD
CY2017	lfus	Income Tax Reconciliation Nondeductible Expense Professional Fees IncomeTaxReconciliationNondeductibleExpenseProfessionalFees	1240000	USD
CY2019	lfus	Effective Income Tax Rate Reconciliation Toll Charge Amount EffectiveIncomeTaxRateReconciliationTollChargeAmount	0	USD
CY2018	lfus	Effective Income Tax Rate Reconciliation Toll Charge Amount EffectiveIncomeTaxRateReconciliationTollChargeAmount	2278000	USD
CY2017	lfus	Effective Income Tax Rate Reconciliation Toll Charge Amount EffectiveIncomeTaxRateReconciliationTollChargeAmount	49000000	USD
CY2019	lfus	Effective Income Tax Rate Reconciliation Provisional Tax Act Impact Other Than Toll Charge Amount EffectiveIncomeTaxRateReconciliationProvisionalTaxActImpactOtherThanTollChargeAmount	0	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	41694000	USD
CY2018Q4	us-gaap	Deferred Tax Liabilities DeferredTaxLiabilities	44523000	USD
CY2018	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	1754000	USD
CY2017	us-gaap	Income Tax Reconciliation Other Adjustments IncomeTaxReconciliationOtherAdjustments	-1504000	USD
CY2019	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	26802000	USD
CY2018	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	40377000	USD
CY2017	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	84518000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Accrued Liabilities DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities	28294000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Accrued Liabilities DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAccruedLiabilities	34113000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards DeferredTaxAssetsOperatingLossCarryforwards	10511000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Operating Loss Carryforwards DeferredTaxAssetsOperatingLossCarryforwards	8613000	USD
CY2019Q4	us-gaap	Deferred Tax Asset Interest Carryforward DeferredTaxAssetInterestCarryforward	5324000	USD
CY2018Q4	us-gaap	Deferred Tax Asset Interest Carryforward DeferredTaxAssetInterestCarryforward	885000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Credit Carryforwards Research DeferredTaxAssetsTaxCreditCarryforwardsResearch	2581000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Tax Credit Carryforwards Research DeferredTaxAssetsTaxCreditCarryforwardsResearch	1245000	USD
CY2019Q4	lfus	Deferred Tax Assets Capitalized Expense DeferredTaxAssetsCapitalizedExpense	2400000	USD
CY2018Q4	lfus	Deferred Tax Assets Capitalized Expense DeferredTaxAssetsCapitalizedExpense	0	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Credit Carryforwards Foreign DeferredTaxAssetsTaxCreditCarryforwardsForeign	1320000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Tax Credit Carryforwards Foreign DeferredTaxAssetsTaxCreditCarryforwardsForeign	1506000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Tax Credit Carryforwards Other DeferredTaxAssetsTaxCreditCarryforwardsOther	1261000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Tax Credit Carryforwards Other DeferredTaxAssetsTaxCreditCarryforwardsOther	1000000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	51691000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Gross DeferredTaxAssetsGross	47362000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	5957000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Valuation Allowance DeferredTaxAssetsValuationAllowance	4794000	USD
CY2019Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	45734000	USD
CY2018Q4	us-gaap	Deferred Tax Assets Net DeferredTaxAssetsNet	42568000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	74460000	USD
CY2018Q4	us-gaap	Deferred Tax Liabilities Property Plant And Equipment DeferredTaxLiabilitiesPropertyPlantAndEquipment	74410000	USD
CY2019Q4	us-gaap	Deferred Tax Liabilities Undistributed Foreign Earnings DeferredTaxLiabilitiesUndistributedForeignEarnings	12968000	USD
CY2018Q4	us-gaap	Deferred Tax Liabilities Undistributed Foreign Earnings DeferredTaxLiabilitiesUndistributedForeignEarnings	12681000	USD
CY2019Q4	us-gaap	Deferred Income Tax Liabilities DeferredIncomeTaxLiabilities	87428000	USD
CY2019	lfus	Income Tax Holiday Expense Benefit Amount Per Diluted Share IncomeTaxHolidayExpenseBenefitAmountPerDilutedShare	-0.17
CY2019	us-gaap	Income Tax Examination Interest Expense IncomeTaxExaminationInterestExpense	1300000	USD
CY2019	lfus	Income Tax Examination Decrease Dueto Lapseof Statuteof Limitations IncomeTaxExaminationDecreaseDuetoLapseofStatuteofLimitations	600000	USD
CY2018	us-gaap	Income Tax Examination Interest Expense IncomeTaxExaminationInterestExpense	1500000	USD
CY2018	lfus	Income Tax Examination Decrease Dueto Lapseof Statuteof Limitations IncomeTaxExaminationDecreaseDuetoLapseofStatuteofLimitations	300000	USD
CY2017	us-gaap	Income Tax Examination Interest Expense IncomeTaxExaminationInterestExpense	900000	USD
CY2019Q4	us-gaap	Income Tax Examination Interest Accrued IncomeTaxExaminationInterestAccrued	7200000	USD
CY2019	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	92503000	USD
CY2019	us-gaap	Income Taxes Paid IncomeTaxesPaid	47600000	USD
CY2018	us-gaap	Income Taxes Paid IncomeTaxesPaid	46200000	USD
CY2017	us-gaap	Income Taxes Paid IncomeTaxesPaid	31800000	USD
CY2019	us-gaap	Proceeds From Income Tax Refunds ProceedsFromIncomeTaxRefunds	7100000	USD
CY2018	us-gaap	Proceeds From Income Tax Refunds ProceedsFromIncomeTaxRefunds	4300000	USD
CY2017	us-gaap	Proceeds From Income Tax Refunds ProceedsFromIncomeTaxRefunds	13700000	USD
CY2019Q4	us-gaap	Undistributed Earnings Of Foreign Subsidiaries UndistributedEarningsOfForeignSubsidiaries	776000000	USD
CY2019Q4	lfus	Deferred Tax Liabilities Recognizedon Undistributed Foreign Earnings DeferredTaxLiabilitiesRecognizedonUndistributedForeignEarnings	13000000.0	USD
CY2018Q4	lfus	Deferred Tax Liabilities Recognizedon Undistributed Foreign Earnings DeferredTaxLiabilitiesRecognizedonUndistributedForeignEarnings	12700000	USD
CY2017Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	7660000	USD
CY2018	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	2929000	USD
CY2018	us-gaap	Unrecognized Tax Benefits Increases Resulting From Acquisition UnrecognizedTaxBenefitsIncreasesResultingFromAcquisition	9394000	USD
CY2018	us-gaap	Unrecognized Tax Benefits Reductions Resulting From Lapse Of Applicable Statute Of Limitations UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations	1257000	USD
CY2018	lfus	Unrecognized Tax Benefits Decrease Resulting From Other Positions UnrecognizedTaxBenefitsDecreaseResultingFromOtherPositions	467000	USD
CY2018Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	18259000	USD
CY2019	us-gaap	Unrecognized Tax Benefits Increases Resulting From Current Period Tax Positions UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions	1305000	USD
CY2019	us-gaap	Unrecognized Tax Benefits Reductions Resulting From Lapse Of Applicable Statute Of Limitations UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations	2758000	USD
CY2019	lfus	Unrecognized Tax Benefits Decrease Resulting From Other Positions UnrecognizedTaxBenefitsDecreaseResultingFromOtherPositions	85000	USD
CY2019Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	16721000	USD
CY2018Q4	us-gaap	Income Tax Examination Interest Accrued IncomeTaxExaminationInterestAccrued	5900000	USD
CY2019Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	16700000	USD
CY2018Q4	us-gaap	Unrecognized Tax Benefits UnrecognizedTaxBenefits	18300000	USD
CY2019Q4	us-gaap	Decrease In Unrecognized Tax Benefits Is Reasonably Possible DecreaseInUnrecognizedTaxBenefitsIsReasonablyPossible	100000	USD
CY2017	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	22687000	shares
CY2018	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	103193000	USD
CY2017	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	63011000	USD
CY2019	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	242000	shares
CY2018	us-gaap	Operating Income Loss OperatingIncomeLoss	225049000	USD
CY2018	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	365000	shares
CY2017	us-gaap	Weighted Average Number Diluted Shares Outstanding Adjustment WeightedAverageNumberDilutedSharesOutstandingAdjustment	244000	shares
CY2019	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	24818000	shares
CY2018	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	391972	shares
CY2019	us-gaap	Profit Loss ProfitLoss	139082000	USD
CY2018	us-gaap	Profit Loss ProfitLoss	164565000	USD
CY2017	us-gaap	Profit Loss ProfitLoss	119519000	USD
CY2019	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	24576000	shares
CY2018	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	24870000	shares
CY2018	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	25235000	shares
CY2017	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	22931000	shares
CY2019	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	5.66
CY2018	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	6.62
CY2017	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	5.27
CY2019	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	5.60
CY2018	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	6.52
CY2017	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	5.21
CY2019	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	129658	shares
CY2018	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	42305	shares
CY2017	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	37443	shares
CY2019	us-gaap	Treasury Stock Shares Acquired TreasuryStockSharesAcquired	579916	shares
CY2019	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	95000000.0	USD
CY2018	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	67900000	USD
CY2019	us-gaap	Number Of Operating Segments NumberOfOperatingSegments	3	segment
CY2019	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	1503873000	USD
CY2018	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	1718468000	USD
CY2017	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	1221534000	USD
CY2019	us-gaap	Operating Income Loss OperatingIncomeLoss	192791000	USD
CY2019	us-gaap	Restructuring Costs And Asset Impairment Charges RestructuringCostsAndAssetImpairmentCharges	13000000.0	USD
CY2019Q1	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	405500000	USD
CY2018Q4	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	402281000	USD
CY2018Q3	us-gaap	Gross Profit GrossProfit	179594000	USD
CY2019	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	583000	USD
CY2018	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	1599000	USD
CY2017	us-gaap	Other Nonoperating Income Expense OtherNonoperatingIncomeExpense	1282000	USD
CY2019	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	165884000	USD
CY2018	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	204942000	USD
CY2017	us-gaap	Income Loss From Continuing Operations Before Income Taxes Extraordinary Items Noncontrolling Interest IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest	204037000	USD
CY2017	us-gaap	Operating Income Loss OperatingIncomeLoss	218511000	USD
CY2019	us-gaap	Interest Expense InterestExpense	22266000	USD
CY2018	us-gaap	Interest Expense InterestExpense	22569000	USD
CY2017	us-gaap	Interest Expense InterestExpense	13380000	USD
CY2019	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	-5224000	USD
CY2018	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	863000	USD
CY2017	us-gaap	Foreign Currency Transaction Gain Loss Before Tax ForeignCurrencyTransactionGainLossBeforeTax	-2376000	USD
CY2019	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	1503873000	USD
CY2018	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	1718468000	USD
CY2017	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	1221534000	USD
CY2019Q4	us-gaap	Noncurrent Assets NoncurrentAssets	344617000	USD
CY2018Q4	us-gaap	Noncurrent Assets NoncurrentAssets	339894000	USD
CY2017Q4	us-gaap	Noncurrent Assets NoncurrentAssets	250577000	USD
CY2019	us-gaap	Property Plant And Equipment Additions PropertyPlantAndEquipmentAdditions	66366000	USD
CY2018	us-gaap	Property Plant And Equipment Additions PropertyPlantAndEquipmentAdditions	74753000	USD
CY2017	us-gaap	Property Plant And Equipment Additions PropertyPlantAndEquipmentAdditions	65925000	USD
CY2019Q4	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	338523000	USD
CY2019Q3	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	361971000	USD
CY2019Q2	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	397879000	USD
CY2018Q3	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	439191000	USD
CY2018Q2	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	459183000	USD
CY2018Q1	us-gaap	Revenue From Contract With Customer Including Assessed Tax RevenueFromContractWithCustomerIncludingAssessedTax	417813000	USD
CY2019Q4	us-gaap	Gross Profit GrossProfit	113467000	USD
CY2019Q3	us-gaap	Gross Profit GrossProfit	130946000	USD
CY2019Q2	us-gaap	Gross Profit GrossProfit	141808000	USD
CY2019Q1	us-gaap	Gross Profit GrossProfit	155228000	USD
CY2018Q4	us-gaap	Gross Profit GrossProfit	154337000	USD
CY2018Q3	us-gaap	Operating Income Loss OperatingIncomeLoss	76228000	USD
CY2019Q2	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	1.75
CY2019Q1	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	1.48
CY2018Q2	us-gaap	Operating Income Loss OperatingIncomeLoss	59622000	USD
CY2018Q4	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	1.29
CY2018Q3	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	2.10
CY2018Q2	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	1.67
CY2018Q1	us-gaap	Operating Income Loss OperatingIncomeLoss	37571000	USD
CY2018Q2	us-gaap	Gross Profit GrossProfit	168987000	USD
CY2018Q1	us-gaap	Gross Profit GrossProfit	149623000	USD
CY2019Q4	us-gaap	Operating Income Loss OperatingIncomeLoss	32317000	USD
CY2019Q3	us-gaap	Operating Income Loss OperatingIncomeLoss	47167000	USD
CY2019Q2	us-gaap	Operating Income Loss OperatingIncomeLoss	52634000	USD
CY2019Q1	us-gaap	Operating Income Loss OperatingIncomeLoss	60673000	USD
CY2018Q4	us-gaap	Operating Income Loss OperatingIncomeLoss	51628000	USD
CY2019Q4	us-gaap	Profit Loss ProfitLoss	22654000	USD
CY2019Q3	us-gaap	Profit Loss ProfitLoss	35647000	USD
CY2019Q2	us-gaap	Profit Loss ProfitLoss	43792000	USD
CY2019Q1	us-gaap	Profit Loss ProfitLoss	36989000	USD
CY2018Q4	us-gaap	Profit Loss ProfitLoss	32665000	USD
CY2018Q3	us-gaap	Profit Loss ProfitLoss	53546000	USD
CY2018Q2	us-gaap	Profit Loss ProfitLoss	42326000	USD
CY2018Q1	us-gaap	Profit Loss ProfitLoss	36029000	USD
CY2019Q4	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	0.93
CY2019Q3	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	1.46
CY2019Q2	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	1.77
CY2019Q1	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	1.50
CY2018Q4	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	1.31
CY2018Q3	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	2.13
CY2018Q2	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	1.69
CY2018Q1	us-gaap	Income Loss From Continuing Operations Per Basic Share IncomeLossFromContinuingOperationsPerBasicShare	1.48
CY2019Q4	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	0.92
CY2019Q3	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	1.44
CY2018Q1	us-gaap	Income Loss From Continuing Operations Per Diluted Share IncomeLossFromContinuingOperationsPerDilutedShare	1.45
CY2019Q4	us-gaap	Business Combination Acquisition Related Costs BusinessCombinationAcquisitionRelatedCosts	1900000	USD
CY2019Q4	us-gaap	Restructuring Costs And Asset Impairment Charges RestructuringCostsAndAssetImpairmentCharges	2100000	USD
CY2019Q4	us-gaap	Asset Impairment Charges AssetImpairmentCharges	4200000	USD
CY2019Q4	us-gaap	Unrecognized Tax Benefits Reductions Resulting From Lapse Of Applicable Statute Of Limitations UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations	3300000	USD
CY2019Q3	us-gaap	Business Combination Acquisition Related Costs BusinessCombinationAcquisitionRelatedCosts	3200000	USD
CY2019Q3	us-gaap	Restructuring Costs And Asset Impairment Charges RestructuringCostsAndAssetImpairmentCharges	2500000	USD
CY2019Q2	us-gaap	Restructuring Costs And Asset Impairment Charges RestructuringCostsAndAssetImpairmentCharges	5700000	USD
CY2019Q2	us-gaap	Business Combination Acquisition Related Costs BusinessCombinationAcquisitionRelatedCosts	1500000	USD
CY2019Q2	us-gaap	Gain Loss On Disposition Of Assets1 GainLossOnDispositionOfAssets1	400000	USD
CY2019Q1	us-gaap	Disposal Group Not Discontinued Operation Gain Loss On Disposal DisposalGroupNotDiscontinuedOperationGainLossOnDisposal	2600000	USD
CY2019Q2	us-gaap	Asset Impairment Charges AssetImpairmentCharges	200000	USD
CY2019Q1	us-gaap	Asset Impairment Charges AssetImpairmentCharges	2800000	USD
CY2019Q1	us-gaap	Gain Loss On Sale Of Business GainLossOnSaleOfBusiness	-2600000	USD
CY2019Q1	us-gaap	Restructuring Costs RestructuringCosts	2700000	USD
CY2019Q1	us-gaap	Business Combination Acquisition Related Costs BusinessCombinationAcquisitionRelatedCosts	2400000	USD
CY2019Q1	us-gaap	Business Combination Step Acquisition Equity Interest In Acquiree Remeasurement Gain BusinessCombinationStepAcquisitionEquityInterestInAcquireeRemeasurementGain	300000	USD
CY2018Q4	us-gaap	Tax Cuts And Jobs Act Of2017 Income Tax Expense Benefit TaxCutsAndJobsActOf2017IncomeTaxExpenseBenefit	3200000	USD
CY2018Q4	us-gaap	Unrecognized Tax Benefits Reductions Resulting From Lapse Of Applicable Statute Of Limitations UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations	1500000	USD
CY2018Q4	us-gaap	Business Combination Acquisition Related Costs BusinessCombinationAcquisitionRelatedCosts	3200000	USD
CY2018Q4	us-gaap	Restructuring Costs RestructuringCosts	2400000	USD
CY2018Q3	us-gaap	Restructuring Costs RestructuringCosts	5200000	USD
CY2018Q3	us-gaap	Business Combination Acquisition Related Costs BusinessCombinationAcquisitionRelatedCosts	2900000	USD
CY2018Q2	us-gaap	Restructuring Costs RestructuringCosts	4200000	USD
CY2018Q2	us-gaap	Business Combination Acquisition Related Costs BusinessCombinationAcquisitionRelatedCosts	2400000	USD
CY2018Q1	lfus	Purchase Accounting Inventory Adjustments PurchaseAccountingInventoryAdjustments	17900000	USD
CY2018Q1	us-gaap	Business Combination Acquisition Related Costs BusinessCombinationAcquisitionRelatedCosts	11700000	USD
CY2018Q1	lfus	Business Combination Backlog Amortization Costs BusinessCombinationBacklogAmortizationCosts	2500000	USD
CY2018Q1	us-gaap	Restructuring Costs RestructuringCosts	800000	USD
CY2019Q4	us-gaap	Cost Method Investments CostMethodInvestments	400000	USD

Files In Submission

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$LFUS
LITTELFUSE INC /DE Stock $lfus

2018 Q4 Form 10-K Financial Statement

#000088933120000014 Filed on February 21, 2020

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$LFUS LITTELFUSE INC /DE Stock $lfus

2018 Q4 Form 10-K Financial Statement

#000088933120000014 Filed on February 21, 2020

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$LFUS
LITTELFUSE INC /DE Stock $lfus