Selected Segment Financial Data, Assets (Detail) (USD $) In Thousands	Jun. 30, 2011	Dec. 31, 2010
Segment Reporting Information [Line Items]
Assets	$ 613,647	$ 601,529
Americas - United States
Segment Reporting Information [Line Items]
Assets	349,556	335,457
Americas - Other
Segment Reporting Information [Line Items]
Assets	23,732	21,254
EMEA
Segment Reporting Information [Line Items]
Assets	177,824	186,209
Asia /Pacific
Segment Reporting Information [Line Items]
Assets	$ 62,535	$ 58,609