Note 10 - Coal Mining Liability	12 Months Ended
Dec. 27, 2014
Other Liabilities and Financial Instruments Subject to Mandatory Redemption [Abstract]
Other Liabilities Disclosure [Text Block]	10. Coal Mining Liability Included in other long-term liabilities is an accrual related to former coal mining operations at Littelfuse GmbH (formerly known as Heinrich Industries, AG) for the amounts of €1.9 million ($2.4 million) and €2.2 million ($3.1 million) at December 27, 2014 and December 28, 2013, respectively. Management, in conjunction with an independent third-party, performs an annual evaluation of the former coal mining operations in order to develop an estimate of the probable future obligations in regard to remediating the dangers (such as a shaft collapse) of abandoned coal mine shafts in the former coal mining operations. Management accrues for costs associated with such remediation efforts based on management's best estimate when such costs are probable and reasonably able to be estimated. The ultimate determination can only be done after respective investigations because the concrete conditions are mostly unknown at this time. The accrual is not discounted as management cannot reasonably estimate when such remediation efforts will take place.

Note 10 - Coal Mining Liability

12 Months Ended

Dec. 27, 2014

Other Liabilities and Financial Instruments Subject to Mandatory Redemption [Abstract]

Other Liabilities Disclosure [Text Block]

10. Coal Mining Liability

Included in other long-term liabilities is an accrual related to former coal mining operations at Littelfuse GmbH (formerly known as Heinrich Industries, AG) for the amounts of €1.9 million ($2.4 million) and €2.2 million ($3.1 million) at December 27, 2014 and December 28, 2013, respectively. Management, in conjunction with an independent third-party, performs an annual evaluation of the former coal mining operations in order to develop an estimate of the probable future obligations in regard to remediating the dangers (such as a shaft collapse) of abandoned coal mine shafts in the former coal mining operations. Management accrues for costs associated with such remediation efforts based on management's best estimate when such costs are probable and reasonably able to be estimated. The ultimate determination can only be done after respective investigations because the concrete conditions are mostly unknown at this time. The accrual is not discounted as management cannot reasonably estimate when such remediation efforts will take place.