Derivative Financial Instruments - Fair Values of Assets and Liabilities Measured and Recognized at Fair Value (Detail) (USD $) In Thousands, unless otherwise specified	Apr. 30, 2013	Oct. 31, 2012
Derivative assets:
Derivative assets	$ 4,620
Fair Value, Measurements, Recurring [Member]
Derivative liabilities:
Total fair value	4,620	7,496
Fair Value, Measurements, Recurring [Member] | Other receivables [Member]
Derivative assets:
Derivative assets	6,480	11,356
Fair Value, Measurements, Recurring [Member] | Other assets [Member]
Derivative assets:
Derivative assets	507
Fair Value, Measurements, Recurring [Member] | Accrued liabilities [Member]
Derivative liabilities:
Derivative liabilities	(2,367)	(3,860)
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Derivative liabilities:
Total fair value	4,620	7,496
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Other receivables [Member]
Derivative assets:
Derivative assets	6,480	11,356
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Other assets [Member]
Derivative assets:
Derivative assets	507
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Accrued liabilities [Member]
Derivative liabilities:
Derivative liabilities	$ (2,367)	$ (3,860)