Segment Reporting - Segment Information About Reported Segment Product Revenues by Product Category (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Product revenues	$ 259,540	$ 240,056	$ 624,214	$ 741,303
Automotive Segments
Segment Reporting Information [Line Items]
Product revenues	249,764	228,243	590,622	700,300
Automotive Segments | Climate Control Seats (CCS)
Segment Reporting Information [Line Items]
Product revenues	97,058	88,133	229,465	270,924
Automotive Segments | Seat Heaters
Segment Reporting Information [Line Items]
Product revenues	73,471	71,030	171,345	218,578
Automotive Segments | Automotive Cables
Segment Reporting Information [Line Items]
Product revenues	18,917	20,361	50,890	66,316
Automotive Segments | Steering Wheel Heaters
Segment Reporting Information [Line Items]
Product revenues	22,506	16,621	49,721	49,620
Automotive Segments | Battery Thermal Management (BTM)
Segment Reporting Information [Line Items]
Product revenues	15,956	11,890	33,818	31,531
Automotive Segments | Electronics
Segment Reporting Information [Line Items]
Product revenues	14,463	11,729	38,327	36,035
Automotive Segments | Other Automotive
Segment Reporting Information [Line Items]
Product revenues	7,393	8,479	17,056	27,296
Industrial Segments
Segment Reporting Information [Line Items]
Product revenues	9,776	11,813	33,592	41,003
Industrial Segments | Medical
Segment Reporting Information [Line Items]
Product revenues	$ 9,776	8,336	$ 33,592	26,404
Industrial Segments | GPT
Segment Reporting Information [Line Items]
Product revenues		$ 3,477		11,181
Industrial Segments | CSZ-IC
Segment Reporting Information [Line Items]
Product revenues				$ 3,418