Allowance for Doubtful Accounts Activity (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	$ 583	$ 621	$ 577
Charged to costs and expenses	61	256	772
Write-offs, net of recoveries	160	294	728
Balance at end of period	$ 484	$ 583	$ 621