Accounts Receivable, Net (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Receivables [Abstract]
Trade	$ 57,740	$ 52,663
Due from affiliates, net	18,089	20,971
Settlement assets	8,949	5,938
Other	321	144
Less: allowance for doubtful accounts	(1,771)	(1,913)
Accounts receivable, net	$ 83,328	$ 77,803