Valuation and Qualifying Accounts (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Valuation Allowance for Deferred Tax Assets
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of period		$ 79,264	$ 70,227	$ 56,333
Charges to costs and expenses (income)		(3,987)	9,037	13,894
Balance at end of period		$ 75,277	79,264	70,227
Allowance for Doubtful Accounts Receivable
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at beginning of period	[1]		$ 480,289	410,374
Charges to costs and expenses (income)	[1]			869,077
Write-off of uncollectible accounts	[1]			(799,162)
Balance at end of period	[1]			$ 480,289

[1] Effective January 1, 2018, the Company adopted ASC 606 using a modified retrospective approach.  This schedule discloses allowance for doubtful accounts receivable for periods reported under ASC 605 only.