Summary of Significant Accounting Policies - Summary of Allowance for Doubtful Accounts Activity (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accounting Policies [Abstract]
Allowance for doubtful accounts, Beginning Balance	$ 2,087	$ 2,038
Provision for doubtful accounts	1,892	2,149	$ 1,825
Write-offs, net of recoveries	(1,892)	(2,100)
Allowance for doubtful accounts, Ending Balance	$ 2,087	$ 2,087	$ 2,038