Inventory step-up recorded in an acquisition.

No definition available.

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Data Type:	xbrli:monetaryItemType
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- Definition

Non-cash charges related to inventory step-up.

+ References

No definition available.

+ Details

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Namespace Prefix:	lfus_
Data Type:	xbrli:monetaryItemType
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- Details

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- Definition

Percentage of voting equity interests acquired at the acquisition date in the business combination.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=25497992&loc=d3e1392-128463

+ Details

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Namespace Prefix:	us-gaap_
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Period Type:	instant

- Definition

Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Investing Activities

-URI http://asc.fasb.org/extlink&oid=6516133

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 13

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3213-108585

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Balance Type:	credit
Period Type:	duration

Note 3 - Acquisition of Businesses (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	1 Months Ended	3 Months Ended		1 Months Ended	3 Months Ended
	Mar. 30, 2013 Accel AB [Member] Licensing Agreements [Member]	May 31, 2012 Accel AB [Member]	Sep. 29, 2012 Accel AB [Member]	Mar. 30, 2013 Cole Hersee Company [Member] Trademarks [Member]	Sep. 26, 2012 Terra Power [Member]	Mar. 30, 2013 Minimum [Member] Selco A/S [Member] Distribution Rights [Member]	Mar. 30, 2013 Maximum [Member] Selco A/S [Member] Distribution Rights [Member]
Note 3 - Acquisition of Businesses (Details) [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired		100.00%			100.00%
Payments to Acquire Businesses, Gross (in Dollars)		$ 23.9			$ 10.6
Finite-Lived Intangible Asset, Useful Life	10 years			5 years		3 years	10 years
Business Acquisition, Inventory Step-up (in Dollars)		0.4
Non-cash Charges Related to Inventory Step-up (in Dollars)			$ 0.4