Material accounting policies - Additional information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2025 USD ($) segment	Dec. 31, 2024
Statement [line items]
Number of operating segments \| segment	2
Driver IC CGU
Statement [line items]
Annual discount rate	9.59%	9.04%
WLO CGU
Statement [line items]
Annual discount rate	13.73%	13.78%
Growth rate used to extrapolate cash flow projections	2.32%	2.48%
Period for average Taiwan economic growth rate	5 years
Software \| Bottom of range
Statement [line items]
Assets Acquired Useful Life	2 years
Software \| Top of range
Statement [line items]
Assets Acquired Useful Life	10 years
Technology \| Bottom of range
Statement [line items]
Assets Acquired Useful Life	3 years
Technology \| Top of range
Statement [line items]
Assets Acquired Useful Life	7 years
Intellectual Properties \| Bottom of range
Statement [line items]
Assets Acquired Useful Life	10 years
Intellectual Properties \| Top of range
Statement [line items]
Assets Acquired Useful Life	15 years
Himax semi conductor
Statement [line items]
Goodwill recognised as of acquisition date	$ 26,846
Himax Display (USA) Inc
Statement [line items]
Goodwill recognised as of acquisition date	$ 1,292
Buildings
Statement [line items]
Useful Life Of Tangible Assets	25 years
Building and improvements \| Bottom of range
Statement [line items]
Useful Life Of Tangible Assets	4 years
Building and improvements \| Top of range
Statement [line items]
Useful Life Of Tangible Assets	16 years
Machinery \| Bottom of range
Statement [line items]
Useful Life Of Tangible Assets	4 years
Machinery \| Top of range
Statement [line items]
Useful Life Of Tangible Assets	10 years
Research and development equipment \| Bottom of range
Statement [line items]
Useful Life Of Tangible Assets	2 years
Research and development equipment \| Top of range
Statement [line items]
Useful Life Of Tangible Assets	6 years
Office furniture and equipment \| Bottom of range
Statement [line items]
Useful Life Of Tangible Assets	3 years
Office furniture and equipment \| Top of range
Statement [line items]
Useful Life Of Tangible Assets	8 years
Others \| Bottom of range
Statement [line items]
Useful Life Of Tangible Assets	2 years
Others \| Top of range
Statement [line items]
Useful Life Of Tangible Assets	10 years
Embedded software \| Bottom of range
Statement [line items]
Useful Life Of Tangible Assets	2 years
Embedded software \| Top of range
Statement [line items]
Useful Life Of Tangible Assets	10 years