Segment Information - Additional Information (Detail)	6 Months Ended	3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended			12 Months Ended
	Jun. 30, 2013 Segment	Jun. 30, 2013 Customer Concentration Risk Sales Revenue, Goods, Net Customer	Jun. 30, 2012 Customer Concentration Risk Sales Revenue, Goods, Net Customer	Jun. 30, 2013 Customer Concentration Risk Sales Revenue, Goods, Net Customer	Jun. 30, 2012 Customer Concentration Risk Sales Revenue, Goods, Net Customer	Jun. 30, 2013 Geographic Concentration Risk Sales Revenue, Goods, Net Country	Jun. 30, 2012 Geographic Concentration Risk Sales Revenue, Goods, Net Country	Jun. 30, 2013 Geographic Concentration Risk Sales Revenue, Goods, Net Country	Jun. 30, 2012 Geographic Concentration Risk Sales Revenue, Goods, Net Country	Jun. 30, 2013 Geographic Concentration Risk Assets, Total Country	Dec. 31, 2012 Geographic Concentration Risk Assets, Total Country
Segment Reporting Information
Number of operating segments	1
Number Of Individual Country accounted for 10% or more of total revenues						0	0	0	0
Number Of Individual Customer accounted for 10% or more of total consolidated revenues		0	0	0	0
Number Of Individual country accounted for 10% or more of total consolidated assets										0	0