Consolidated Balance Sheets (Unaudited) (Parenthetical) (USD $) In Millions, except Share data	Jun. 30, 2011	Dec. 31, 2010
Receivables:
Allowance for doubtful receivables	$ 0.6	$ 0.6
Stockholders' equity:
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	90,000,000	90,000,000
Common stock, shares issued	19,285,825	19,214,451
Common stock, shares outstanding	19,285,825	19,214,451
Common stock owned by Union VEBA, shares	2,202,495	3,523,980
Treasury stock, shares	1,724,606	1,724,606