Derivative And Other Financial Instruments (Narratives) (Details) gal in Millions, T in Millions, BTU in Trillions	3 Months Ended
	Mar. 31, 2018 EUR (€) BTU gal T	Mar. 31, 2017	Mar. 31, 2018 USD ($) BTU gal T	Dec. 31, 2017 EUR (€) gal T	Dec. 31, 2017 USD ($) gal T
Derivative [Line Items]
Cash collateral posted | $			$ 0		$ 0
Metal
Derivative [Line Items]
Maximum settlement period of derivatives (in months)	3 months
Tons of metal in forward contracts with the right to buy (in tons)	0.2		0.2	0.1	0.1
Tons of metal in forward contracts with the right to sell (in tons)	0.2		0.2	0.2	0.2
Energy Related Derivative
Derivative [Line Items]
British thermal units in forward buy contracts (in British thermal units) | BTU	3.5		3.5
Gallons in diesel swap contracts (in gallons) | gal	3.5		3.5	1.5	1.5
Currency
Derivative [Line Items]
Euros in forward contracts | €	€ 82,600,000			€ 100,800,000.0
Convertible Notes Payable
Derivative [Line Items]
Risk-free interest rate (percent)	2.30%	1.60%
Expected equity volatility rate (percent)	60.00%
Zhenjiang term loans
Derivative [Line Items]
Maximum period for variable interest rate paid (in months)	6 months
Senior Notes | 7 7/8% Senior Notes
Derivative [Line Items]
Stated interest rate	7.875%		7.875%
Senior Notes | 9 1/2% Senior Notes
Derivative [Line Items]
Stated interest rate	9.50%		9.50%