Summary of Net Sales and Operating Income (Loss) by Segment (Detail) (USD $)
In Thousands, unless otherwise specified
3 Months Ended 6 Months Ended
Apr. 30, 2013
Apr. 30, 2012
Apr. 30, 2013
Apr. 30, 2012
Segment Reporting Information [Line Items]        
Sales revenue, net $ 232,458 $ 194,444 $ 418,171 $ 356,023
Operating income (loss) (9,373) (16,079) (23,058) (27,383)
Engineered Products
       
Segment Reporting Information [Line Items]        
Sales revenue, net 125,158 108,770 231,277 208,163
Operating income (loss) 5,908 83 8,741 1,887
Aluminum Sheet Products
       
Segment Reporting Information [Line Items]        
Sales revenue, net 109,691 88,293 194,294 153,993
Operating income (loss) (468) (7,533) (4,698) (13,051)
Intersegment Eliminations
       
Segment Reporting Information [Line Items]        
Sales revenue, net (2,391) (2,619) (7,400) (6,133)
Corporate and Other
       
Segment Reporting Information [Line Items]        
Operating income (loss) $ (14,813) $ (8,629) $ (27,101) $ (16,219)