Segment Information about Reported Product Revenues and Operating Income (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Segment Reporting Information [Line Items]
Product revenues	$ 206,012	$ 171,182	$ 606,132	$ 479,792
Depreciation and amortization	8,634	7,737	24,565	23,467
Operating income (loss)	24,000	14,554	73,051	32,764
Wet Automotive Ag
Segment Reporting Information [Line Items]
Product revenues	197,480	171,182	589,426	479,792
Depreciation and amortization	7,062	6,477	20,790	21,231
Operating income (loss)	29,534	20,428	105,550	64,114
Industrial Segments
Segment Reporting Information [Line Items]
Product revenues	8,532		16,706
Depreciation and amortization	700	118	1,650	343
Operating income (loss)	(1,832)	(150)	(5,689)	(4,781)
Reconciling Items
Segment Reporting Information [Line Items]
Depreciation and amortization	872	1,142	2,125	1,893
Operating income (loss)	$ (3,702)	$ (5,724)	$ (26,810)	$ (26,569)