Segment Information about Reported Product Revenues, Depreciation and Amortization and Operating Income (Loss) (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Segment Reporting Information [Line Items]
Product revenues	$ 235,853	$ 232,625	$ 728,498	$ 681,059
Depreciation and amortization	11,472	10,177	32,663	27,724
Operating income (loss)	16,177	27,415	76,249	79,653
Operating Segments \| Automotive Segments
Segment Reporting Information [Line Items]
Product revenues	215,175	212,369	652,820	634,636
Depreciation and amortization	9,423	8,631	26,602	23,566
Operating income (loss)	37,179	54,408	128,018	133,271
Operating Segments \| Industrial Segments
Segment Reporting Information [Line Items]
Product revenues	20,678	20,256	75,678	46,423
Depreciation and amortization	1,334	989	4,040	2,578
Operating income (loss)	(5,607)	(4,899)	(10,741)	(14,628)
Reconciling Items
Segment Reporting Information [Line Items]
Depreciation and amortization	715	557	2,021	1,580
Operating income (loss)	$ (15,395)	$ (22,094)	$ (41,028)	$ (38,990)

The current period expense charged against earnings on long-lived, physical assets not used in production, and which are not intended for resale, to allocate or recognize the cost of such assets over their useful lives; or to record the reduction in book value of an intangible asset over the benefit period of such asset; or to reflect consumption during the period of an asset that is not used in production.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1(a))
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

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