Derivatives	6 Months Ended
Jun. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives	Derivatives As of June 30, 2018, we had an open position of 3,090 tonnes related to LME forward financial sales contracts, all of which are with Glencore, to fix the forward LME price (the “forward financial sales contracts”). These forward financial sales contracts are expected to settle monthly, on a ratable basis, between November 1, 2019 and December 31, 2020. We also have financial contracts with various counterparties, including Glencore, to offset fixed price sales arrangements with certain of our customers (the “fixed for floating swaps”) to remain exposed to the LME price. As of June 30, 2018, we had open positions related to such arrangements of 8,609 tonnes settling at various dates through September 2019. In 2017, we entered into financial contracts to fix the forward price of approximately 4% of Grundartangi's total power requirements for the period November 1, 2019 through December 31, 2020 (the “power price swaps”). The power price swaps are not designated as cash flow hedges. As of June 30, 2018, we had an open position of 256,200 MWh related to the power price swaps. Because the power price swaps are settled in euros, in 2018 we entered into financial contracts to hedge the risk of fluctuations associated with the euro (the "fx swaps"). As of June 30, 2018, we had open positions related to the fx swaps for €2.8 million euros that settle monthly, on a ratable basis, from November 1, 2019 through December 31, 2020. The fair value for the fx swaps at June 30, 2018 was immaterial. The fx swaps are not designated as cash flow hedges. As of June 30, 2018, we had a derivative asset and liability of $3.2 million and $1.5 million, respectively, in the consolidated balance sheet. At December 31, 2017, we had a derivative asset and liability of $1.7 million and $1.2 million, respectively, in the consolidated balance sheet. For the three and six months ended June 30, 2018, we recognized gains of $1.2 million and $1.9 million, respectively, related to out derivative instruments in the consolidated statements of operations, a portion of which related to transactions with Glencore. For the three months ended June 30, 2017, we recognized a gain of $3.0 million and for the six months ended June 30, 2017, we recognized a loss of $13.2 million in the consolidated statements of operations, substantially all of which related to transactions with Glencore.

Derivatives

As of June 30, 2018, we had an open position of 3,090 tonnes related to LME forward financial sales contracts, all of which are with Glencore, to fix the forward LME price (the “forward financial sales contracts”). These forward financial sales contracts are expected to settle monthly, on a ratable basis, between November 1, 2019 and December 31, 2020. We also have financial contracts with various counterparties, including Glencore, to offset fixed price sales arrangements with certain of our customers (the “fixed for floating swaps”) to remain exposed to the LME price. As of June 30, 2018, we had open positions related to such arrangements of 8,609 tonnes settling at various dates through September 2019.

In 2017, we entered into financial contracts to fix the forward price of approximately 4% of Grundartangi's total power requirements for the period November 1, 2019 through December 31, 2020 (the “power price swaps”). The power price swaps are not designated as cash flow hedges. As of June 30, 2018, we had an open position of 256,200 MWh related to the power price swaps. Because the power price swaps are settled in euros, in 2018 we entered into financial contracts to hedge the risk of fluctuations associated with the euro (the "fx swaps"). As of June 30, 2018, we had open positions related to the fx swaps for €2.8 million euros that settle monthly, on a ratable basis, from November 1, 2019 through December 31, 2020. The fair value for the fx swaps at June 30, 2018 was immaterial. The fx swaps are not designated as cash flow hedges.

As of June 30, 2018, we had a derivative asset and liability of $3.2 million and $1.5 million, respectively, in the consolidated balance sheet. At December 31, 2017, we had a derivative asset and liability of $1.7 million and $1.2 million, respectively, in the consolidated balance sheet.

For the three and six months ended June 30, 2018, we recognized gains of $1.2 million and $1.9 million, respectively, related to out derivative instruments in the consolidated statements of operations, a portion of which related to transactions with Glencore. For the three months ended June 30, 2017, we recognized a gain of $3.0 million and for the six months ended June 30, 2017, we recognized a loss of $13.2 million in the consolidated statements of operations, substantially all of which related to transactions with Glencore.