Acquisition of Sebree aluminum smelter (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended			9 Months Ended		16 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Jun. 01, 2013 t
Business Acquisition [Line Items]
Purchase price cash paid				$ 1,042	$ 48,058
Gain on bargain purchase	0		0	0	5,253
Sebree power contract amortization				(5,534)	(14,461)
Sebree Smelter [Member]
Business Acquisition [Line Items]
Sebree primary aluminum capacity (tonnes)							205,000
Purchase price for acquisition							61,000
Purchase price cash paid						49,035
Separately recognized transactions, gains recognized		965
Gain on bargain purchase						5,253
Cash						48,083
Deferred purchase price						1,910
Inventories	59,018			59,018		59,018
Prepaid and other current assets	2,273			2,273		2,273
Property, plant and equipment – net	55,520			55,520		55,520
Total assets acquired	116,811			116,811		116,811
Accrued and other current liabilities	43,316			43,316		43,316
Accrued pension benefit costs	996			996		996
Accrued post retirement benefit costs	6,544			6,544		6,544
Other liabilities	7,476			7,476		7,476
Deferred taxes	3,233			3,233		3,233
Total liabilities assumed	61,565			61,565		61,565
Sebree power contract amortization	0		11,720	5,534	14,461
Pro forma revenues					1,261,533
Pro forma loss from continuing operations					$ (57,853)
Loss per common share, basic					$ (0.65)
Loss per common share, diluted					$ (0.65)