Segments and Geographic Information - Operation by Geographic Location (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Segment Reporting Information [Line Items]
Revenues	$ 402,925	$ 414,371
Americas [Member]
Segment Reporting Information [Line Items]
Revenues	324,777	340,721
Americas [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	324,777	340,721
Americas [Member] | Operating Segments [Member] | United States [Member]
Segment Reporting Information [Line Items]
Revenues	162,032	171,446
Americas [Member] | Operating Segments [Member] | The Philippines [Member]
Segment Reporting Information [Line Items]
Revenues	56,078	60,086
Americas [Member] | Operating Segments [Member] | Costa Rica [Member]
Segment Reporting Information [Line Items]
Revenues	30,717	32,075
Americas [Member] | Operating Segments [Member] | Canada [Member]
Segment Reporting Information [Line Items]
Revenues	25,564	27,189
Americas [Member] | Operating Segments [Member] | El Salvador [Member]
Segment Reporting Information [Line Items]
Revenues	20,476	20,011
Americas [Member] | Operating Segments [Member] | China [Member]
Segment Reporting Information [Line Items]
Revenues	8,903	9,348
Americas [Member] | Operating Segments [Member] | Australia [Member]
Segment Reporting Information [Line Items]
Revenues	7,629	7,702
Americas [Member] | Operating Segments [Member] | Mexico [Member]
Segment Reporting Information [Line Items]
Revenues	6,557	6,318
Americas [Member] | Operating Segments [Member] | Other [Member]
Segment Reporting Information [Line Items]
Revenues	6,821	6,546
EMEA [Member]
Segment Reporting Information [Line Items]
Revenues	78,128	73,627
EMEA [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	78,128	73,627
EMEA [Member] | Operating Segments [Member] | Other [Member]
Segment Reporting Information [Line Items]
Revenues	15,227	13,839
EMEA [Member] | Operating Segments [Member] | Germany [Member]
Segment Reporting Information [Line Items]
Revenues	23,864	24,175
EMEA [Member] | Operating Segments [Member] | Sweden [Member]
Segment Reporting Information [Line Items]
Revenues	13,640	14,130
EMEA [Member] | Operating Segments [Member] | United Kingdom [Member]
Segment Reporting Information [Line Items]
Revenues	16,885	13,347
EMEA [Member] | Operating Segments [Member] | Romania [Member]
Segment Reporting Information [Line Items]
Revenues	8,512	8,136
Other Segment [Member]
Segment Reporting Information [Line Items]
Revenues	$ 20	$ 23