Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2022	Oct. 28, 2022
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q3
Trading Symbol	THRM
Entity Registrant Name	GENTHERM INCORPORATED
Entity Central Index Key	0000903129
Entity Current Reporting Status	Yes
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		33,198,067
Entity Shell Company	false
Entity File Number	0-21810
Entity Tax Identification Number	95-4318554
Entity Address, Address Line One	21680 Haggerty Road
Entity Address, City or Town	Northville
Entity Address, State or Province	MI
Entity Address, Postal Zip Code	48167
City Area Code	248
Local Phone Number	504-0500
Entity Interactive Data Current	Yes
Entity Incorporation, State or Country Code	MI
Document Quarterly Report	true
Security Exchange Name	NASDAQ
Title of 12(b) Security	Common Stock, no par value
Document Transition Report	false