Intangible Assets (Detail) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Gain on sale of intangible assets	$ 0	$ 15,000	$ 0	$ 15,000	$ 20,000
Intangible assets:
Finite-lived intangible assets	642,677			642,677		$ 307,995
Indefinite-lived intangible assets	0			0		326,359
Gross intangible assets:	642,677			642,677		634,354
Less: Accumulated amortization	(179,828)			(179,828)		(142,546)
Net carrying value	$ 462,849			$ 462,849		$ 491,808	[1]
Restatement Adjustment
Intangible assets:
Finite-lived intangible assets		326,400
Indefinite-lived intangible assets		$ (326,400)

[1] December 31, 2018 balances were derived from the audited Consolidated Financial Statements included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2018, filed with the SEC on February 28, 2019.