Income Taxes (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Income (Loss) Before Income Taxes	$ 13.6	$ 10.3	$ 25.2	$ 71.4
Statutory taxes at 35%	4.8	3.6	8.8	25.0
Income Tax Reconciliation, Nondeductible Expense	(0.3)	(0.2)	(0.3)	(0.4)
Tax Adjustments, Settlements, and Unusual Provisions	(0.3)	(0.2)	(0.3)	(0.4)
Effective Income Tax Rate Reconciliation, Percentage Depletion	(1.5)	(0.7)	(2.4)	(3.6)
Effective Income Tax Rate Reconciliation Foreign Tax Rate Differential	(0.1)	(0.7)	(0.1)	(0.8)
Effective Income Tax Rate Reconciliation, Other	0.5	0.1	0.7	1.6
Effective Income Tax Rate Reconciliation Permanent Items	(1.1)	(1.3)	(1.8)	(2.8)
Income tax provision	$ 3.4	$ 2.1	$ 6.7	$ 21.8
Effective income tax rate	25.00%	20.40%	26.60%	30.50%