Contingencies Contingencies (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2011	Sep. 30, 2015	Nov. 30, 2011
Loss Contingencies [Line Items]
Estimate of EPA's interim removal project costs	$ 1.6			$ 1.6	$ 0.5
Contingency accrual	(1.3)			(2.3)
Patent Infringement Against Orbis Corp
Loss Contingencies [Line Items]
Contingency accrual	3.0	$ (3.0)
Loss Contingency, Range of Possible Loss, Maximum	$ 3.1			$ 3.1
General and Administrative Expense | Environmental Issue | Pending Litigation | New Idria Mercury Mine
Loss Contingencies [Line Items]
Expense related to remedial investigation and feasibility study			$ 1.9
Other Liabilities | Environmental Issue | Pending Litigation | New Idria Mercury Mine
Loss Contingencies [Line Items]
Payments charged against the reserve			$ 0.9