Segments and Geographic Information - Company's Reportable Segments (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information [Line Items]
Revenues	$ 416,833	$ 389,006	$ 827,999	$ 791,931
Percentage of revenues	100.00%	100.00%	100.00%	100.00%
Depreciation, net	$ 12,630	$ 13,052	$ 25,091	$ 26,949
Amortization of intangibles	4,093	4,127	8,212	8,413
Income (loss) from operations	27,213	15,255	51,607	32,007
Total other income (expense), net	1,402	(1,520)	(3,848)	(1,903)
Income taxes	(6,385)	(2,466)	(11,611)	(7,148)
Net income	22,230	11,269	36,148	22,956
Americas [Member]
Segment Reporting Information [Line Items]
Revenues	$ 339,272	$ 310,307	$ 672,198	$ 635,084
Percentage of revenues	81.40%	79.80%	81.20%	80.20%
Americas [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	$ 339,272	$ 310,307	$ 672,198	$ 635,084
Percentage of revenues	81.40%	79.80%	81.20%	80.20%
Depreciation, net	$ 10,088	$ 10,659	$ 20,121	$ 22,166
Amortization of intangibles	3,281	3,288	6,567	6,726
Income (loss) from operations	40,479	26,584	76,258	56,652
EMEA [Member]
Segment Reporting Information [Line Items]
Revenues	$ 77,561	$ 78,676	$ 155,794	$ 156,804
Percentage of revenues	18.60%	20.20%	18.80%	19.80%
EMEA [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	$ 77,561	$ 78,676	$ 155,794	$ 156,804
Percentage of revenues	18.60%	20.20%	18.80%	19.80%
Depreciation, net	$ 1,818	$ 1,628	$ 3,523	$ 3,254
Amortization of intangibles	812	839	1,645	1,687
Income (loss) from operations	$ 4,078	4,661	7,258	6,152
Other Segment [Member]
Segment Reporting Information [Line Items]
Revenues		$ 23	$ 7	$ 43
Percentage of revenues	0.00%	0.00%	0.00%	0.00%
Depreciation, net	$ 724	$ 765	$ 1,447	$ 1,529
Income (loss) from operations	(17,344)	(15,990)	(31,909)	(30,797)
Total other income (expense), net	1,402	(1,520)	(3,848)	(1,903)
Income taxes	$ (6,385)	$ (2,466)	$ (11,611)	$ (7,148)