Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) (USD $)
In Thousands, except Share data, unless otherwise specified
3 Months Ended
Mar. 31, 2014
Mar. 31, 2013
Statements of Comprehensive Income (Loss) [Abstract]    
Sales $ 201,894 $ 209,554
Cost of sales 194,751 200,732
Gross profit 7,143 8,822
Selling expenses 318 167
General and administration expenses 3,482 2,970
Total operating expenses 3,800 3,137
Income from operations 3,343 5,685
Other income (expenses):    
Interest income 2,791 751
Interest expense (4,968) (3,396)
Foreign exchange gain (loss) , net (2,445) 1,553
Other expenses, net (1,460) (380)
Total other income (expenses), net (6,082) (1,472)
(Loss) income before income taxes (2,739) 4,213
Income tax expense    1,295
Net (loss) income attributable to Keyuan Petrochemicals Inc. stockholders (2,739) 2,918
Dividends to Series B convertible preferred stockholders      
Net (loss) income attributable to Keyuan Petrochemicals Inc. common stockholders (2,739) 2,918
Net (loss) income attributable to Keyuan Petrochemicals Inc. stockholders (2,739) 2,918
Other comprehensive (loss) income:    
Foreign currency translation adjustment (837) 531
Comprehensive (loss) income $ (3,576) $ 3,449
(Loss) earnings per share: Attributable to common stock:    
-Basic $ (0.05) $ 0.05
-Diluted $ (0.05) $ 0.05
Weighted average number of shares of common stock used in calculation:    
-Basic 57,505,098 57,646,160
-Diluted 57,505,098 62,979,500