Summary of Significant Accounting Policies - Summary of Changes in Allowance for Doubtful Accounts (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Receivables [Abstract]
Beginning balance – allowance for doubtful accounts	$ 4,759	$ 4,180	$ 4,540
Provision for doubtful accounts	11,856	2,318	2,437
Write-offs	(2,916)	(1,739)	(2,797)
Ending balance – allowance for doubtful accounts	$ 13,699	$ 4,759	$ 4,180