Major Customers - Significant Customers as Percentage of Total Net Sales (Detail)	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Revenue, Major Customer [Line Items]
Percentage of total net sales	10.00%
Customer A [Member]
Revenue, Major Customer [Line Items]
Percentage of total net sales	20.40%	20.70%	19.80%
Customer B [Member]
Revenue, Major Customer [Line Items]
Percentage of total net sales	11.40%	10.50%	9.80%
Customer C [Member]
Revenue, Major Customer [Line Items]
Percentage of total net sales	10.30%	8.90%	8.00%