Pretax Amounts Recognized in Other Comprehensive Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Actuarial (Gains)/losses	$ (35)	$ 213	$ (193)
Amortization of actuarial losses	(27)		(37)
Pretax amounts recognized in other comprehensive income (loss)	(62)	213	(230)
Gentherm GmbH
Defined Benefit Plan Disclosure [Line Items]
Actuarial (Gains)/losses	(154)	1,916	67
Amortization of actuarial losses	(59)	166	37
Amortization of prior service cost	(572)
Pretax amounts recognized in other comprehensive income (loss)	$ (785)	$ 2,082	$ 104