Segment Information about Reported Product Revenues and Operating Income (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Product revenues	$ 811,300us-gaap_SalesRevenueGoodsNet	$ 662,082us-gaap_SalesRevenueGoodsNet	$ 554,979us-gaap_SalesRevenueGoodsNet
Depreciation and amortization	35,029us-gaap_DepreciationAndAmortization	31,249us-gaap_DepreciationAndAmortization	30,627us-gaap_DepreciationAndAmortization
Operating income (loss)	98,434us-gaap_OperatingIncomeLoss	50,384us-gaap_OperatingIncomeLoss	36,656us-gaap_OperatingIncomeLoss
W.E.T
Segment Reporting Information [Line Items]
Product revenues	787,065	662,082	554,979
Depreciation and amortization	30,016	28,439	29,188
Operating income (loss)	144,645	91,255	71,995
Industrial Segments
Segment Reporting Information [Line Items]
Product revenues	24,235
Depreciation and amortization	2,114	323	247
Operating income (loss)	(8,922)	(5,860)	(5,252)
Reconciling Items
Segment Reporting Information [Line Items]
Depreciation and amortization	2,899	2,487	1,192
Operating income (loss)	$ (37,289)	$ (35,011)	$ (30,087)

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

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Reference 2: http://www.xbrl.org/2003/role/presentationRef

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-Name Accounting Standards Codification

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

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Reference 2: http://www.xbrl.org/2003/role/presentationRef

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