Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 58,828	$ 57,455
Accumulated Amortization	7,609	6,245
Net Carrying Amount	51,189	51,210
Trademarks and patents
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,019	879
Accumulated Amortization	161	140
Net Carrying Amount	828	739
Technology
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	36,514	35,769
Accumulated Amortization	5,762	4,655
Net Carrying Amount	30,752	31,114
Covenant not-to-compete
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	978	956
Accumulated Amortization	188	135
Net Carrying Amount	790	821
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	20,317	19,851
Accumulated Amortization	1,498	1,315
Net Carrying Amount	$ 18,819	$ 18,536