Derivative Instruments and Hedging Activities (Details) $ in Millions	9 Months Ended
	Sep. 30, 2017 USD ($) MMBTU MW t lb	Sep. 30, 2017 CAD MMBTU MW t lb	Sep. 30, 2017 EUR (€) MMBTU MW t lb	Dec. 31, 2016 CAD MMBTU MW t lb	Dec. 31, 2016 EUR (€) MMBTU MW t lb
Derivative [Line Items]
Derivative, Collateral, Right to Reclaim Cash	$ 0.0
Canada, Dollars
Derivative [Line Items]
Beginning Settlement Date	Jan. 01, 2018
Ending Settlement Date	Dec. 31, 2019
Gains (losses) expected to be reclassified into cost of products sold within the next twelve months	$ (0.4)
Natural Gas [Member]
Derivative [Line Items]
Beginning Settlement Date	Oct. 01, 2017
Ending Settlement Date	Oct. 31, 2019
Gains (losses) expected to be reclassified into cost of products sold within the next twelve months	$ 5.4
Zinc [Member]
Derivative [Line Items]
Beginning Settlement Date	Oct. 01, 2017
Ending Settlement Date	Jun. 30, 2019
Gains (losses) expected to be reclassified into cost of products sold within the next twelve months	$ 10.6
Electricity [Member]
Derivative [Line Items]
Beginning Settlement Date	Oct. 01, 2017
Ending Settlement Date	Dec. 31, 2018
Gains (losses) expected to be reclassified into cost of products sold within the next twelve months	$ (0.4)
Commodity Contract [Member] | Natural Gas [Member]
Derivative [Line Items]
Nonmonetary Notional Amount of Derivatives | MMBTU	37,475,000	37,475,000	37,475,000	43,865,000	43,865,000
Commodity Contract [Member] | Zinc [Member]
Derivative [Line Items]
Nonmonetary Notional Amount of Derivatives | lb	40,350,000	40,350,000	40,350,000	58,750,000	58,750,000
Commodity Contract [Member] | Iron Ore [Member]
Derivative [Line Items]
Nonmonetary Notional Amount of Derivatives | t	2,375,000	2,375,000	2,375,000	2,555,000	2,555,000
Commodity Contract [Member] | Electricity [Member]
Derivative [Line Items]
Nonmonetary Notional Amount of Derivatives | MW	1,182,000	1,182,000	1,182,000	1,578,821	1,578,821
Foreign Exchange Contract [Member] | Euro Member Countries, Euro
Derivative [Line Items]
Derivative, Notional Amount | €			€ 9,000,000		€ 5,000,000
Foreign Exchange Contract [Member] | Canada, Dollars
Derivative [Line Items]
Derivative, Notional Amount | CAD		CAD 88,620,000		CAD 0