Derivative Instruments and Hedging Activities (Details) $ in Millions	6 Months Ended
	Jun. 30, 2017 USD ($) MMBTU MW t lb	Jun. 30, 2017 EUR (€) MMBTU MW t lb	Dec. 31, 2016 EUR (€) MMBTU MW t lb
Derivative [Line Items]
Derivative, Collateral, Right to Reclaim Cash	$ 0.0
Natural Gas [Member]
Derivative [Line Items]
Beginning Settlement Date	Jul. 01, 2017
Ending Settlement Date	Mar. 31, 2019
Gains (losses) expected to be reclassified into cost of products sold within the next twelve months	$ 6.2
Zinc [Member]
Derivative [Line Items]
Beginning Settlement Date	Jul. 01, 2017
Ending Settlement Date	Jun. 30, 2019
Gains (losses) expected to be reclassified into cost of products sold within the next twelve months	$ 6.2
Electricity [Member]
Derivative [Line Items]
Beginning Settlement Date	Jul. 01, 2017
Ending Settlement Date	Dec. 31, 2018
Gains (losses) expected to be reclassified into cost of products sold within the next twelve months	$ (1.0)
Commodity Contract [Member] | Natural Gas [Member]
Derivative [Line Items]
Nonmonetary Notional Amount of Derivatives | MMBTU	35,818,000	35,818,000	43,865,000
Commodity Contract [Member] | Zinc [Member]
Derivative [Line Items]
Nonmonetary Notional Amount of Derivatives | lb	47,600,000	47,600,000	58,750,000
Commodity Contract [Member] | Iron Ore [Member]
Derivative [Line Items]
Nonmonetary Notional Amount of Derivatives | t	2,280,000	2,280,000	2,555,000
Commodity Contract [Member] | Electricity [Member]
Derivative [Line Items]
Nonmonetary Notional Amount of Derivatives | MW	1,140,000	1,140,000	1,578,821
Foreign Exchange Contract [Member]
Derivative [Line Items]
Derivative, Notional Amount | €		€ 12,000,000	€ 5,000,000