Joint Ventures (Summarized Information for Joint Ventures) (Details) (USD $)
In Thousands, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Equity Method Investments and Joint Ventures [Abstract]    
Net sales $ 10,978 $ 11,332
Gross profit 3,445 3,652
Net income $ 1,839 $ 1,955