Borrowings - Components of Long-Term Debt (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Nov. 20, 2017	May 21, 2014
Line Of Credit Facility [Line Items]
Long-term debt, Gross	$ 2,176,500	$ 2,270,000
Less: Unamortized debt issuance costs	(17,675)	(20,448)
Net carrying amount	2,158,825	2,249,552
Current portion of borrowings	(86,625)	(86,625)
Long-term borrowings	2,072,200	2,162,927
Revolving Credit Facility
Line Of Credit Facility [Line Items]
Revolving credit facility, at a rate of 4.27% at December 31, 2018 and 3.44% at December 31, 2017, due 2022	$ 293,000	$ 349,000
Senior credit facility interest rate	4.27%	3.57%
Securitization Program
Line Of Credit Facility [Line Items]
Securitization program, at a rate of 3.25% at December 31, 2018 and 2.31% at December 31, 2017	$ 50,000	$ 50,000
Interest rate	3.25%	2.31%
Term loan facility, at a rate of 4.27% at December 31, 2018 and 3.57% at December 31 2017, due 2022 | Term Loan
Line Of Credit Facility [Line Items]
Revolving credit facility, at a rate of 4.27% at December 31, 2018 and 3.44% at December 31, 2017, due 2022	$ 683,500	$ 721,000
Senior credit facility interest rate	4.27%	3.57%
5.25% Senior Notes due 2024 | Senior Notes
Line Of Credit Facility [Line Items]
Senior notes	$ 250,000	$ 250,000		$ 250,000
Interest rate	5.25%	5.25%		5.25%
4.875% Senior Notes due 2026 | Senior Notes
Line Of Credit Facility [Line Items]
Senior notes	$ 400,000	$ 400,000
Interest rate	4.875%	4.875%
4.625% Senior Notes due 2027 | Senior Notes
Line Of Credit Facility [Line Items]
Senior notes	$ 500,000	$ 500,000	$ 500,000
Interest rate	4.625%	4.625%	4.625%