Customer Relationships and Other Intangibles, Net - Details of Customer Relationships and Other Intangibles, Net (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross	$ 139,063	$ 137,776
Accumulated Amortization	(74,402)	(66,969)
Net	64,661	70,807
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross	116,529	116,711
Accumulated Amortization	(64,041)	(57,811)
Net	52,488	58,900
Purchased and internally developed software
Finite-Lived Intangible Assets [Line Items]
Gross	7,718	6,226
Accumulated Amortization	(5,340)	(4,871)
Net	2,378	1,355
Trademarks
Finite-Lived Intangible Assets [Line Items]
Gross	14,816	14,839
Accumulated Amortization	(5,021)	(4,287)
Net	$ 9,795	$ 10,552

Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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