Derivatives	12 Months Ended
Dec. 31, 2017
Summary of Derivative Instruments [Abstract]
Derivatives	Derivatives At December 31, 2017, 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 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. At December 31, 2017 we had an open position related to such arrangements of 8,964 tonnes settling at various dates through December 2018. We have also 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. At December 31, 2017 we had an open position of 256,200 MWh related to the power price swaps. At December 31, 2017, we had a derivative asset and liability of $1,724 and $1,200, respectively, in the consolidated balance sheets. In 2017, we recognized a loss of $16,549 related to our derivative instruments in the consolidated statements of operations, substantially all of which related to transactions with Glencore. The impact of the derivative instruments on the consolidated balance sheets and consolidated statements of operations was not material for the corresponding prior periods presented.

Derivatives

At December 31, 2017, 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 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. At December 31, 2017 we had an open position related to such arrangements of 8,964 tonnes settling at various dates through December 2018.

We have also 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. At December 31, 2017 we had an open position of 256,200 MWh related to the power price swaps.

At December 31, 2017, we had a derivative asset and liability of $1,724 and $1,200, respectively, in the consolidated balance sheets. In 2017, we recognized a loss of $16,549 related to our derivative instruments in the consolidated statements of operations, substantially all of which related to transactions with Glencore. The impact of the derivative instruments on the consolidated balance sheets and consolidated statements of operations was not material for the corresponding prior periods presented.