Impairment of Long-Lived Assets - Additional information (Detail)	3 Months Ended		12 Months Ended
	Dec. 31, 2015 USD ($) $ / bbl	Dec. 31, 2014 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Impairment Of Long Lived Assets [Line Items]
Loss (gain) on disposal or impairment of assets			$ (44,111,000)	$ (15,079,000)	$ 43,000
Impairment of long-lived assets	$ 36,177,000		5,896,000	2,138,000
Deterioration of oil price | $ / bbl	30
Industry fully recovery period	5 years
Reclassification of China cumulative translation gain to Net Loss upon substantial liquidation			(8,853,000)
Gain on disposal of assets			230,000	41,000	43,000
Long Lived Asset Impairments
Impairment Of Long Lived Assets [Line Items]
Loss (gain) on disposal or impairment of assets			(43,697,000)	(15,120,000)
Bauxite raw materials
Impairment Of Long Lived Assets [Line Items]
Impairment of long-term portion of the bauxite raw material	$ 6,488,000		6,488,000
Falcon
Impairment Of Long Lived Assets [Line Items]
Impairment of goodwill			8,664,000
Impairment of trademark			$ 833,000
StrataGen
Impairment Of Long Lived Assets [Line Items]
Impairment of goodwill				0	0
Marshfield, Wisconsin
Impairment Of Long Lived Assets [Line Items]
Impairment of long-lived assets				4,956,000	$ 0
Georgia
Impairment Of Long Lived Assets [Line Items]
Period Required to Resume Production			2 years
Period Required to Return to Production Levels at Normal Capacity			4 years
Impairment of long-lived assets			$ 0
Georgia | Millen
Impairment Of Long Lived Assets [Line Items]
Production idling period			90 days
Georgia | Toomsboro
Impairment Of Long Lived Assets [Line Items]
Production idling period			90 days
CHINA
Impairment Of Long Lived Assets [Line Items]
Impairment of long-lived assets		$ 10,164,000
Reclassification of China cumulative translation gain to Net Loss upon substantial liquidation	8,853,000		$ 8,853,000
China assets impairment	$ 1,033,000		$ 1,033,000	$ 10,164,000