Note 12 - Benefit Plans (Details) - Weighted Average Assumptions	12 Months Ended
	Dec. 31, 2013	Dec. 28, 2013	Dec. 31, 2012	Dec. 31, 2011
Note 12 - Benefit Plans (Details) - Weighted Average Assumptions [Line Items]
Expected return on plan assets		6.80%
Littelfuse, Inc. Plan [Member] | United States Pension Plan of US Entity, Defined Benefit [Member]
Note 12 - Benefit Plans (Details) - Weighted Average Assumptions [Line Items]
Discount rate				5.90%	[1]
Expected return on plan assets				8.50%	[2]
Cole Hersee Plan [Member] | United States Pension Plan of US Entity, Defined Benefit [Member]
Note 12 - Benefit Plans (Details) - Weighted Average Assumptions [Line Items]
Discount rate				5.40%	[1]
Expected return on plan assets				7.50%	[2]
United States Pension Plan of US Entity, Defined Benefit [Member]
Note 12 - Benefit Plans (Details) - Weighted Average Assumptions [Line Items]
Discount rate	3.90%		5.40%
Expected return on plan assets	6.80%		7.80%
Measurement dates	12/31/13		12/31/12	12/31/11
Discount rate	4.80%		3.90%	5.40%
Foreign Pension Plan, Defined Benefit [Member]
Note 12 - Benefit Plans (Details) - Weighted Average Assumptions [Line Items]
Discount rate	4.50%		5.50%	5.30%
Expected return on plan assets	4.80%	4.80%	4.50%	4.50%
Compensation increase rate	3.60%		5.60%	5.30%
Measurement dates	12/31/13		12/31/12	12/31/11
Discount rate	4.50%		4.20%	5.50%
Compensation increase rate	3.80%		6.30%	5.60%

[1] 5.9% used for the Littelfuse, Inc. Retirement Plan, and 5.4% used for the Cole Hersee plan.

[2] 8.5% used for the Littelfuse, Inc. Retirement Plan, and 7.5% used for the Cole Hersee plan.