Significant Concentrations and Risks (Details) (USD $)
In Thousands, unless otherwise specified
3 Months Ended
Mar. 31, 2014
Mar. 31, 2013
Revenue, Major Customer [Line Items]    
Amount of Sales $ 201,894 $ 209,554
Customer A [Member]
   
Revenue, Major Customer [Line Items]    
Amount of Sales 23,740  
% Total Sales 12.00%  
Customer B [Member]
   
Revenue, Major Customer [Line Items]    
Amount of Sales   $ 30,853
% Total Sales   15.00%