Document And Entity Information (USD $)	12 Months Ended
	Dec. 28, 2013	Feb. 14, 2014	Jun. 29, 2013
Document and Entity Information [Abstract]
Entity Registrant Name	LITTELFUSE INC /DE
Document Type	10-K
Current Fiscal Year End Date	--12-28
Entity Common Stock, Shares Outstanding		22,460,247
Entity Public Float			$ 1,658,139,355
Amendment Flag	true
Amendment Description	Littelfuse, Inc. (the "Company," "we," "us" or "our") is filing this Amendment No. 1 on Form 10-K/A to our Annual Report on Form 10-K for the year ended December 28, 2013, originally filed with the Securities and Exchange Commission (the "SEC") on February 25, 2014 (the "Original Form 10-K"), in response to a comment received from the SEC regarding a revision to the report of independent registered public accounting firm for omitted language.In response to the SEC's comment, this Form 10-K/A sets forth the Original Form 10-K in its entirety with the exception of the report of independent registered public accounting firm, which has been amended and restated in its entirety to correct for previously omitted language.Other than the revision discussed above, this Form 10-K/A speaks as of the original filing date of the Original Form 10-K and has not been updated to reflect other events occurring subsequent to the original filing date. This includes forward-looking statements and all other sections of this Form 10-K/A that were not revised, which should be read in their historical context.In response to the SEC's comment, this Form 10-K/A includes Item 8, including an updated report of independent registered public accounting firm to correct for previously omitted language and which remains dated February 25, 2014, Item 9A and Item 15.Other than the revision discussed above, this Form 10-K/A speaks as of the original filing date of the Original Form 10-K and has not been updated to reflect other events occurring subsequent to the original filing date. This includes forward-looking statements and all other sections of this Form 10-K/A that were not revised, which should be read in their historical context.
Entity Central Index Key	0000889331
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Well-known Seasoned Issuer	Yes
Document Period End Date	Dec. 28, 2013
Document Fiscal Year Focus	2013
Document Fiscal Period Focus	FY