Segment Information - Segment's Contribution with Respect to Net Revenue, Operating Expenses, Operating Income (Loss) and Total Assets (Parenthetical) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Benefit pursuant to tax receivable agreement	$ 6,495	$ 202,546
LTBP Trust [Member]
Segment Reporting Information [Line Items]
Benefit pursuant to tax receivable agreement	6,495	202,546
Corporate [Member] | LTBP Trust [Member]
Segment Reporting Information [Line Items]
Benefit pursuant to tax receivable agreement	$ 6,495	$ 202,546