Inventories (Details Textual) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
Inventories (Textual) [Abstract]
Terms of precious metals consignment agreements, maximum			1 year
Fees under precious metals consignment agreements	$ 1.7	$ 2.7	$ 3.6	$ 4.7
Fair value of precious metals on hand under consignment agreements	$ 178.1		$ 178.1		$ 195.0