Non-cash charges related to inventory step-up.

No definition available.

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

- Definition

Non-Cash Credit Related To Inventory Stepup

+ References

No definition available.

+ Details

Name:	lfus_NoncashCreditRelatedToInventoryStepup
Namespace Prefix:	lfus_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

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- Definition

Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

+ References

+ Details

Name:	us-gaap_AssetImpairmentCharges
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 25

-Paragraph 23

-URI http://asc.fasb.org/extlink&oid=34752592&loc=d3e1043-128460

+ Details

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Balance Type:	debit
Period Type:	duration

- Definition

The amount by which the fair value of an investment is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income.

+ References

+ Details

Name:	us-gaap_ImpairmentOfInvestments
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.4-08.(h))

-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 08

-Paragraph h

-Article 4

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Income Tax Expense (or Benefit)

-URI http://asc.fasb.org/extlink&oid=6515339

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 9

-Subparagraph (a),(b)

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32639-109319

+ Details

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Balance Type:	debit
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- Definition

Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 420

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 420

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SAB TOPIC 5.P.4(b))

-URI http://asc.fasb.org/extlink&oid=27011515&loc=d3e140904-122747

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 420

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SAB TOPIC 5.P.3)

-URI http://asc.fasb.org/extlink&oid=27011515&loc=d3e140864-122747

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 5

-Section P

-Subsection 3, 4

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of expenses for special or contractual termination benefits provided to current employees involuntarily terminated under a benefit arrangement associated exit or disposal activities pursuant to an authorized plan. Excludes expenses related to one-time termination benefits, a discontinued operation or an asset retirement obligation.

+ References

+ Details

Name:	us-gaap_SeveranceCosts1
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

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- Details

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- Details

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Note 18 - Selected Quarterly Financial Data (Unaudited) (Details) (USD $)	3 Months Ended		12 Months Ended			3 Months Ended
	Dec. 27, 2014	Sep. 27, 2014	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012	Dec. 28, 2013	Mar. 30, 2013	Jun. 28, 2014	Mar. 29, 2014	Sep. 28, 2013	Jun. 29, 2013
Note 18 - Selected Quarterly Financial Data (Unaudited) (Details) [Line Items]
Restructuring Charges	$ 2,200,000us-gaap_RestructuringCharges	$ 1,100,000us-gaap_RestructuringCharges
Business Combination, Acquisition Related Costs	300,000		500,000	1,700,000	900,000
Asset Impairment Charges	300,000us-gaap_AssetImpairmentCharges			0us-gaap_AssetImpairmentCharges	500,000us-gaap_AssetImpairmentCharges
Income Tax Expense (Benefit)			32,228,000us-gaap_IncomeTaxExpenseBenefit	35,451,000us-gaap_IncomeTaxExpenseBenefit	24,720,000us-gaap_IncomeTaxExpenseBenefit
Shocking [Member]
Note 18 - Selected Quarterly Financial Data (Unaudited) (Details) [Line Items]
Income Tax Expense (Benefit)						2,800,000	3,300,000
Other than Temporary Impairment Losses, Investments					3,300,000		10,700,000
SymCom, Inc. [Member]
Note 18 - Selected Quarterly Financial Data (Unaudited) (Details) [Line Items]
Business Combination, Acquisition Related Costs								200,000
Non-cash Charges Related to Inventory Step-up								1,400,000	1,400,000
Severance Costs								2,000,000
Hamlin, Inc. [Member]
Note 18 - Selected Quarterly Financial Data (Unaudited) (Details) [Line Items]
Business Combination, Acquisition Related Costs						200,000				300,000	1,200,000
Non-cash Charges Related to Inventory Step-up								500,000		300,000	1,700,000
Non-Cash Credit Related To Inventory Stepup						$ 500,000