Components of Net Periodic Pension Benefit Cost (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 387	$ 379	$ 335
Interest cost	98	80	78
Amortization of actuarial loss (gains)		27
Net periodic benefit cost	485	486	413
Gentherm GmbH
Defined Benefit Plan Disclosure [Line Items]
Service cost			304
Interest cost	154	142	181
Return on plan assets	(125)	(126)	(89)
Amortization of prior service cost		572
Amortization of actuarial loss (gains)	48	59	(166)
Net periodic benefit cost	$ 77	$ 647	$ 230