Related-Party Transactions (Details) (USD $)	3 Months Ended		46 Months Ended		3 Months Ended	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2012 Traxys North America LLC and affiliates	Dec. 31, 2011 Traxys North America LLC and affiliates	Dec. 31, 2011 Traxys North America LLC and affiliates Lanthanum oxide	Dec. 31, 2011 Traxys North America LLC and affiliates Yttrium and bastnasite material	Dec. 31, 2011 Traxys North America LLC and affiliates Tantalum Metal	Mar. 31, 2012 Traxys North America LLC and affiliates Tantalum Metal
Related Party Transactions
Principal payments made	$ 870,000	$ 935,000	$ 5,127,000		$ 900,000	$ 3,100,000
Outstanding amount of short-term borrowing payable to related party				870,000		900,000
Outstanding amount of trade accounts payable related to sales made to related party but not remitted						2,800,000
Purchases made from related party							6,200,000	700,000
Related party receivables									2,100,000	400,000
Sales to related party									3,200,000
Payable to related party					$ 65,000	$ 169,000