Revenue, Credit Concentrations and Geographic Information - Additional Information (Detail) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2019 USD ($) Segment	Dec. 31, 2018 USD ($)
Concentration Risk And Geographic Information [Line Items]
Number of operating business segment | Segment	1
Accounts receivable, net	$ 402,970	$ 342,633	[1]
Customers
Concentration Risk And Geographic Information [Line Items]
Accounts receivable, net	$ 67,700	$ 73,900
Credit Concentration Risk | Accounts Receivable | Customer One
Concentration Risk And Geographic Information [Line Items]
Concentration risk, percentage	23.00%	30.00%
Credit Concentration Risk | Accounts Receivable | Customer Two
Concentration Risk And Geographic Information [Line Items]
Concentration risk, percentage	14.00%	16.00%
Credit Concentration Risk | Accounts Receivable | Customer Three
Concentration Risk And Geographic Information [Line Items]
Concentration risk, percentage	12.00%

[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.