Schedule II- Valuation and Qualifying Accounts (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Allowance for Doubtful Accounts
Valuation and Qualifying Accounts Disclosure [Line Items]
Beginning balance	$ 30,600	$ 54,742	$ 67,057
Provisions for Doubtful Accounts	6,527	(6,711)	8,203
Write-offs, Net of Recoveries	(4,433)	(17,431)	(20,518)
Ending balance	32,694	30,600	54,742
Valuation Allowance of Deferred Tax Assets
Valuation and Qualifying Accounts Disclosure [Line Items]
Beginning balance	3,390,467	3,286,723	3,330,878
Provisions for Doubtful Accounts	201,282	112,543	32,130
Write-offs, Net of Recoveries	(947,850)	(8,799)	(76,285)
Ending balance	$ 2,643,899	$ 3,390,467	$ 3,286,723