Pretax Amounts Recognized in Other Comprehensive Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Actuarial Losses/(gains)	$ 36	$ (35)	$ 213
Amortization of actuarial (losses)/gains		(27)
Pretax amounts recognized in other comprehensive income (loss)	36	(62)	213
Gentherm GmbH
Defined Benefit Plan Disclosure [Line Items]
Actuarial Losses/(gains)	718	(154)	1,916
Amortization of actuarial (losses)/gains	(48)	(59)	166
Amortization of prior service cost		(572)
Pretax amounts recognized in other comprehensive income (loss)	$ (670)	$ (785)	$ 2,082