Segment Reporting - Additional Information (Detail) (Walmart)	6 Months Ended
	Jun. 30, 2012
Revenue, Major Customer [Line Items]
Sales to major customer, percentage	31.80%
North America
Revenue, Major Customer [Line Items]
Sales to major customer, percentage	36.80%
United Kingdom
Revenue, Major Customer [Line Items]
Sales to major customer, percentage	15.50%
Mexico
Revenue, Major Customer [Line Items]
Sales to major customer, percentage	22.40%