Supplemental Financial Information - Summary of Additions and Deductions Related to Allowances for Doubtful Accounts (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Allowance for doubtful accounts receivable, Beginning Balance	$ 10,158	$ 9,138	$ 11,872
Allowance for doubtful accounts receivable, Additions	4,776	5,245	2,452
Allowance for doubtful accounts receivable, Deductions	(4,472)	(4,225)	(5,186)
Allowance for doubtful accounts receivable, Ending Balance	$ 10,462	$ 10,158	$ 9,138