Inventories (Details Textual)	3 Months Ended	12 Months Ended
	Mar. 31, 2013 T	Dec. 31, 2012 T	Dec. 31, 2011 T
Inventories (Textual) [Abstract]
Estimated short of annual minimum coke production (in tons)			122,000
Contract to procure from third party (in tons)			133,000
Quantity of coke agreed to sell on consignment (in tons)			95,000
Total coke consumed by customer (in tons)	22,000	73,000