Segment Information - Selected Segment Financial Data, Revenues and Income Before Income Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Segment Reporting Information [Line Items]
Revenues	$ 238,701	$ 249,644	$ 737,340	$ 725,925
Income before income taxes	18,566	25,165	50,750	29,069
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Income before income taxes	(45,267)	(51,815)	(123,528)	(149,366)
Americas - United States [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	135,504	156,650	442,042	447,737
Americas - Other [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	22,787	16,268	57,730	57,695
EMEA [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	60,558	56,793	178,446	161,604
Income before income taxes	34,893	30,186	89,088	72,526
Asia/Pacific [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	19,852	19,933	59,122	58,889
Income before income taxes	10,041	9,048	28,613	25,130
Americas [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Income before income taxes	$ 18,899	$ 37,746	$ 56,577	$ 80,779