Allowance for Doubtful Account Activity (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at beginning of period	$ 577	$ 793	$ 457
Charged to costs and expenses	772	594	453
Write-offs, net of recoveries	728	810	117
Balance at end of period	$ 621	$ 577	$ 793