Summary of Significant Accounting Policies and Other Information - Revenue Disaggregation (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 27, 2025	Sep. 28, 2024	Sep. 27, 2025	Sep. 28, 2024
Disaggregation of Revenue
Net sales	$ 624,640	$ 567,390	$ 1,792,360	$ 1,661,263
Electronics Segment
Disaggregation of Revenue
Net sales	357,457	304,188	1,000,372	900,932
Transportation Segment
Disaggregation of Revenue
Net sales	171,311	171,381	512,573	510,711
Industrial Segment
Disaggregation of Revenue
Net sales	95,872	91,821	279,415	249,620
Electronics – Semiconductor
Disaggregation of Revenue
Net sales	174,073	151,954	499,329	469,389
Electronics – Semiconductor \| Electronics Segment
Disaggregation of Revenue
Net sales	174,073	151,954	499,329	469,389
Electronics – Semiconductor \| Transportation Segment
Disaggregation of Revenue
Net sales	0	0	0	0
Electronics – Semiconductor \| Industrial Segment
Disaggregation of Revenue
Net sales	0	0	0	0
Electronics – Passive Products and Sensors
Disaggregation of Revenue
Net sales	183,384	152,234	501,043	431,543
Electronics – Passive Products and Sensors \| Electronics Segment
Disaggregation of Revenue
Net sales	183,384	152,234	501,043	431,543
Electronics – Passive Products and Sensors \| Transportation Segment
Disaggregation of Revenue
Net sales	0	0	0	0
Electronics – Passive Products and Sensors \| Industrial Segment
Disaggregation of Revenue
Net sales	0	0	0	0
Commercial Vehicle Products
Disaggregation of Revenue
Net sales	80,272	82,077	244,301	242,350
Commercial Vehicle Products \| Electronics Segment
Disaggregation of Revenue
Net sales	0	0	0	0
Commercial Vehicle Products \| Transportation Segment
Disaggregation of Revenue
Net sales	80,272	82,077	244,301	242,350
Commercial Vehicle Products \| Industrial Segment
Disaggregation of Revenue
Net sales	0	0	0	0
Passenger Car Products
Disaggregation of Revenue
Net sales	75,636	71,299	220,822	210,597
Passenger Car Products \| Electronics Segment
Disaggregation of Revenue
Net sales	0	0	0	0
Passenger Car Products \| Transportation Segment
Disaggregation of Revenue
Net sales	75,636	71,299	220,822	210,597
Passenger Car Products \| Industrial Segment
Disaggregation of Revenue
Net sales	0	0	0	0
Automotive Sensors
Disaggregation of Revenue
Net sales	15,403	18,005	47,450	57,764
Automotive Sensors \| Electronics Segment
Disaggregation of Revenue
Net sales	0	0	0	0
Automotive Sensors \| Transportation Segment
Disaggregation of Revenue
Net sales	15,403	18,005	47,450	57,764
Automotive Sensors \| Industrial Segment
Disaggregation of Revenue
Net sales	0	0	0	0
Industrial Products
Disaggregation of Revenue
Net sales	95,872	91,821	279,415	249,620
Industrial Products \| Electronics Segment
Disaggregation of Revenue
Net sales	0	0	0	0
Industrial Products \| Transportation Segment
Disaggregation of Revenue
Net sales	0	0	0	0
Industrial Products \| Industrial Segment
Disaggregation of Revenue
Net sales	$ 95,872	$ 91,821	$ 279,415	$ 249,620

LITTELFUSE INC /DE 10-Q