Selected Segment Financial Data, Assets (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Segment Reporting Information [Line Items]
Long-lived assets	$ 309,312	$ 278,577
Assets	664,642	601,529
Americas - United States
Segment Reporting Information [Line Items]
Long-lived assets	225,094	189,389
Assets	408,038	335,457
Americas - Other
Segment Reporting Information [Line Items]
Long-lived assets	4,051	4,547
Assets	26,664	21,254
EMEA
Segment Reporting Information [Line Items]
Long-lived assets	56,542	59,494
Assets	166,997	186,209
Asia /Pacific
Segment Reporting Information [Line Items]
Long-lived assets	23,625	25,147
Assets	$ 62,943	$ 58,609