Goodwill and Intangible Assets - Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 57,425	$ 59,115
Accumulated Amortization	12,170	11,045
Net Carrying Amount	45,255	48,070
Trademarks and patents [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,031	1,065
Accumulated Amortization	236	227
Net Carrying Amount	795	838
Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	35,527	36,479
Accumulated Amortization	9,285	8,394
Net Carrying Amount	26,242	28,085
Covenant not-to-compete [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	996	1,042
Accumulated Amortization	405	358
Net Carrying Amount	591	684
Customer relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	19,871	20,529
Accumulated Amortization	2,244	2,066
Net Carrying Amount	$ 17,627	$ 18,463