Segments and Geographic Information - Company's Reportable Segments (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Segment Reporting Information [Line Items]
Revenues	$ 448,885	$ 416,833	$ 906,771	$ 827,999
Percentage of revenues	100.00%	100.00%	100.00%	100.00%
Depreciation, net	$ 12,809	$ 12,630	$ 25,924	$ 25,091
Amortization of intangibles	2,959	4,093	5,946	8,212
Income (loss) from operations	29,721	27,213	61,251	51,607
Total other income (expense), net	(187)	1,402	(834)	(3,848)
Income taxes	(6,354)	(6,385)	(12,259)	(11,611)
Net income	23,180	22,230	48,158	36,148
Americas [Member]
Segment Reporting Information [Line Items]
Revenues	$ 356,427	$ 339,272	$ 720,146	$ 672,198
Percentage of revenues	79.40%	81.40%	79.40%	81.20%
Americas [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	$ 356,427	$ 339,272	$ 720,146	$ 672,198
Percentage of revenues	79.40%	81.40%	79.40%	81.20%
Depreciation, net	$ 9,864	$ 10,088	$ 20,085	$ 20,121
Amortization of intangibles	2,061	3,281	4,157	6,567
Income (loss) from operations	47,275	40,479	92,147	76,258
EMEA [Member]
Segment Reporting Information [Line Items]
Revenues	$ 92,455	$ 77,561	$ 186,622	$ 155,794
Percentage of revenues	20.60%	18.60%	20.60%	18.80%
EMEA [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	$ 92,455	$ 77,561	$ 186,622	$ 155,794
Percentage of revenues	20.60%	18.60%	20.60%	18.80%
Depreciation, net	$ 2,212	$ 1,818	$ 4,368	$ 3,523
Amortization of intangibles	898	812	1,789	1,645
Income (loss) from operations	4,593	$ 4,078	11,261	7,258
Other Segment [Member]
Segment Reporting Information [Line Items]
Revenues	$ 3		$ 3	$ 7
Percentage of revenues	0.00%	0.00%	0.00%	0.00%
Depreciation, net	$ 733	$ 724	$ 1,471	$ 1,447
Income (loss) from operations	(22,147)	(17,344)	(42,157)	(31,909)
Total other income (expense), net	(187)	1,402	(834)	(3,848)
Income taxes	$ (6,354)	$ (6,385)	$ (12,259)	$ (11,611)