Segment Information - Pre-Tax Depreciation and Amortization by Operating Segment (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting Information [Line Items]
Depreciation and amortization of property and equipment	$ 5,524	$ 5,306	$ 15,506	$ 16,018
Amortization of intangible assets	5,946	4,185	13,590	11,399
Depreciation and amortization, total	11,470	9,491	29,096	27,417
North America Segment [Member]
Segment Reporting Information [Line Items]
Depreciation and amortization of property and equipment	4,371	4,131	12,114	12,587
Amortization of intangible assets	5,765	3,949	13,037	10,670
EMEA Segment [Member]
Segment Reporting Information [Line Items]
Depreciation and amortization of property and equipment	1,013	1,052	2,980	3,053
Amortization of intangible assets	67	71	205	216
APAC Segment [Member]
Segment Reporting Information [Line Items]
Depreciation and amortization of property and equipment	140	123	412	378
Amortization of intangible assets	$ 114	$ 165	$ 348	$ 513