Accounts Receivable, Net - Schedule of Changes in the Allowance for Doubtful Accounts on Accounts Receivable (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Receivables [Abstract]
Balance at beginning of period	$ (13,827)	$ (13,508)	$ (12,659)
Provision for losses	(3,776)	(5,529)	(4,154)
Charge-offs, net of recoveries	4,214	5,210	3,305
Balance at end of period	$ (13,389)	$ (13,827)	$ (13,508)