Supplemental Balance Sheet Data (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Supplemental Balance Sheet Data
Raw materials	$ 20.8	$ 17.1
Work in progress	24.7	11.8
Finished goods	64.2	51.6
Supplies and other	2.9	1.7
Inventories, gross	112.6	82.2
Adjust FIFO inventories to LIFO cost	(13.3)	(13.4)
Inventories, net	99.3	68.8
FIFO values of inventories valued on the LIFO method	$ 85.9	$ 59.1