Software and Other Intangible Assets - Carrying Amount and Accumulated Amortization of Other Intangible Assets (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 318,587	$ 321,864
Accumulated Amortization	(139,015)	(130,583)
Net Balance	179,572	191,281
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	302,080	305,218
Accumulated Amortization	(124,465)	(116,677)
Net Balance	177,615	188,541
Trademarks and Tradenames [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	16,507	16,646
Accumulated Amortization	(14,550)	(13,906)
Net Balance	$ 1,957	$ 2,740