Segment Information - Schedule of Revenue from External Customers and Identifiable Assets, by Geographical Areas (Parenthetical) (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2017	Dec. 31, 2015
Segment Reporting Information [Line Items]
Provision (benefit) pursuant to tax receivable agreement	$ 961,948	$ (202,546)	$ 547,691
LTBP Trust [Member]
Segment Reporting Information [Line Items]
Provision (benefit) pursuant to tax receivable agreement		(202,546)	547,691
Americas [Member] | LTBP Trust [Member]
Segment Reporting Information [Line Items]
Provision (benefit) pursuant to tax receivable agreement		$ (202,546)	$ 547,691