Derivative Instruments and Hedging Activities (Details) $ in Millions	6 Months Ended
	Jun. 30, 2016 USD ($) MMBTU MW t lb	Jun. 30, 2016 EUR (€) MMBTU MW t lb	Dec. 31, 2015 EUR (€) MMBTU MW t lb
Derivative [Line Items]
Derivative, Collateral, Right to Reclaim Cash	$ 3.4
Natural Gas [Member]
Derivative [Line Items]
Beginning Settlement Date	Jul. 01, 2016
Ending Settlement Date	Jun. 30, 2018
Gains (losses) expected to be reclassified into cost of products sold within the next twelve months	$ 0.4
Zinc [Member]
Derivative [Line Items]
Beginning Settlement Date	Jul. 01, 2016
Ending Settlement Date	May 31, 2018
Gains (losses) expected to be reclassified into cost of products sold within the next twelve months	$ 0.9
Iron Ore [Member]
Derivative [Line Items]
Beginning Settlement Date	Jul. 01, 2016
Ending Settlement Date	May 31, 2018
Gains (losses) expected to be reclassified into cost of products sold within the next twelve months	$ 1.0
Electricity [Member]
Derivative [Line Items]
Beginning Settlement Date	Jul. 01, 2016
Ending Settlement Date	Dec. 31, 2017
Gains (losses) expected to be reclassified into cost of products sold within the next twelve months	$ (0.4)
Commodity Contract [Member] | Nickel [Member]
Derivative [Line Items]
Nonmonetary Notional Amount of Derivatives | lb	39,000	39,000	164,800
Commodity Contract [Member] | Natural Gas [Member]
Derivative [Line Items]
Nonmonetary Notional Amount of Derivatives | MMBTU	45,593,000	45,593,000	36,972,500
Commodity Contract [Member] | Zinc [Member]
Derivative [Line Items]
Nonmonetary Notional Amount of Derivatives | lb	41,351,000	41,351,000	54,173,800
Commodity Contract [Member] | Iron Ore [Member]
Derivative [Line Items]
Nonmonetary Notional Amount of Derivatives | t	2,095,000	2,095,000	2,795,000
Commodity Contract [Member] | Electricity [Member]
Derivative [Line Items]
Nonmonetary Notional Amount of Derivatives | MW	1,408,000	1,408,000	1,386,400
Foreign Exchange Contract [Member]
Derivative [Line Items]
Derivative, Notional Amount | €		€ 18,050,000	€ 55,500,000