Segment Reporting - Segment Information About Reported Segment Product Revenues by Product Category (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Product revenues	$ 913,098	$ 971,684	$ 1,048,505
Automotive Segments
Segment Reporting Information [Line Items]
Product revenues	869,998	920,225	957,824
Automotive Segments | Climate Control Seat (CCS)
Segment Reporting Information [Line Items]
Product revenues	342,550	359,355	373,945
Automotive Segments | Seat Heaters
Segment Reporting Information [Line Items]
Product revenues	249,665	284,174	305,337
Automotive Segments | Steering Wheel Heaters
Segment Reporting Information [Line Items]
Product revenues	76,272	65,426	69,845
Automotive Segments | Automotive Cables
Segment Reporting Information [Line Items]
Product revenues	73,997	88,031	98,931
Automotive Segments | Electronics
Segment Reporting Information [Line Items]
Product revenues	53,238	47,542	56,783
Automotive Segments | Battery Thermal Management (BTM)
Segment Reporting Information [Line Items]
Product revenues	50,901	41,498	28,472
Automotive Segments | Other Automotive
Segment Reporting Information [Line Items]
Product revenues	23,375	34,199	24,511
Industrial Segments
Segment Reporting Information [Line Items]
Product revenues	43,100	51,459	90,681
Industrial Segments | Medical
Segment Reporting Information [Line Items]
Product revenues	$ 43,100	36,860	30,108
Industrial Segments | GPT
Segment Reporting Information [Line Items]
Product revenues		11,181	19,520
Industrial Segments | CSZ-IC
Segment Reporting Information [Line Items]
Product revenues		$ 3,418	$ 41,053