Acquisition - Fair Values of Assets Acquired and Liabilities Assumed at Date of Closing (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Business Acquisition [Line Items]
Deferred income tax liability	$ (4,207)	$ (128)
Aarding Thermal Acoustics [Member]
Business Acquisition [Line Items]
Current assets	15,062
Property and equipment	959
Goodwill	8,242
Intangible - finite life, net	13,477
Intangible - indefinite life	2,865
Total assets acquired	40,605
Current liabilities assumed	(8,277)
Deferred income tax liability	(4,086)
Net assets acquired	$ 28,242