Inventories (Details Textual) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Inventories (Textual) [Abstract]
Gross inventories under LIFO method	$ 195.7	$ 183.7
Reduction in cost of sales by the liquidation of LIFO inventory layers	$ 0.5	$ 0.2