Selected Segment Financial Data, Revenues and Operating Income (Loss) (Detail) (USD $) In Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Segment Reporting Information [Line Items]
Revenues	$ 112,149	$ 97,017	$ 330,058	$ 277,183
Operating income	11,268	7,388	29,188	10,849
Americas
Segment Reporting Information [Line Items]
Revenues	59,845	49,950	170,149	146,451
Operating income	11,764	7,594	27,405	17,482
EMEA
Segment Reporting Information [Line Items]
Revenues	38,608	35,067	122,629	97,446
Operating income	2,816	3,928	13,212	4,145
Asia /Pacific
Segment Reporting Information [Line Items]
Revenues	13,696	12,000	37,280	33,286
Operating income	$ (3,312)	$ (4,134)	$ (11,429)	$ (10,778)