Financial Instruments and Fair Value Measurements (Details) (USD $) In Thousands	Jul. 31, 2011
Recurring fair value measurements
Total Fair Value	$ (3,551)
Interest rate derivatives [Member] | Fair Value, Inputs, Level 1 [Member] | Other Long-Term Liabilities [Member]
Recurring fair value measurements
Total Fair Value	0
Interest rate derivatives [Member] | Fair Value, Inputs, Level 2 [Member] | Other Long-Term Liabilities [Member]
Recurring fair value measurements
Total Fair Value	671
Interest rate derivatives [Member] | Fair Value, Inputs, Level 3 [Member] | Other Long-Term Liabilities [Member]
Recurring fair value measurements
Total Fair Value	0
Interest rate derivatives [Member] | Other Long-Term Liabilities [Member]
Recurring fair value measurements
Total Fair Value	671
Foreign exchange hedges [Member] | Fair Value, Inputs, Level 1 [Member] | Other Current Liabilities [Member]
Recurring fair value measurements
Total Fair Value	0
Foreign exchange hedges [Member] | Fair Value, Inputs, Level 2 [Member] | Other Current Liabilities [Member]
Recurring fair value measurements
Total Fair Value	2,853
Foreign exchange hedges [Member] | Fair Value, Inputs, Level 3 [Member] | Other Current Liabilities [Member]
Recurring fair value measurements
Total Fair Value	0
Foreign exchange hedges [Member] | Other Current Liabilities [Member]
Recurring fair value measurements
Total Fair Value	2,853
Energy hedges [Member] | Fair Value, Inputs, Level 1 [Member] | Other Current Liabilities [Member]
Recurring fair value measurements
Total Fair Value	0
Energy hedges [Member] | Fair Value, Inputs, Level 2 [Member] | Other Current Liabilities [Member]
Recurring fair value measurements
Total Fair Value	27
Energy hedges [Member] | Fair Value, Inputs, Level 3 [Member] | Other Current Liabilities [Member]
Recurring fair value measurements
Total Fair Value	0
Energy hedges [Member] | Other Current Liabilities [Member]
Recurring fair value measurements
Total Fair Value	27
Fair Value, Inputs, Level 1 [Member]
Recurring fair value measurements
Total Fair Value	0
Fair Value, Inputs, Level 2 [Member]
Recurring fair value measurements
Total Fair Value	(3,551)
Fair Value, Inputs, Level 3 [Member]
Recurring fair value measurements
Total Fair Value	$ 0