Fair Value of Financial Instruments (Details) (USD $) In Thousands, unless otherwise specified	Jul. 31, 2012	Jul. 31, 2011
Financial assets at fair value
Total financial assets, Fair Value	$ 44,524	$ 82,076
Financial liabilities at fair value
Total financial liabilities, Fair Value	4,405	8,438
Level 1 [Member]
Financial assets at fair value
Total financial assets, Fair Value	42,512	71,774
Financial liabilities at fair value
Total financial liabilities, Fair Value
Level 2 [Member]
Financial assets at fair value
Total financial assets, Fair Value	2,012	10,302
Financial liabilities at fair value
Total financial liabilities, Fair Value	4,405	8,438
Level 3 [Member]
Financial assets at fair value
Total financial assets, Fair Value
Financial liabilities at fair value
Total financial liabilities, Fair Value
Carrying Value [Member]
Financial assets at fair value
Total financial assets, Fair Value	44,524	82,076
Financial liabilities at fair value
Total financial liabilities, Fair Value	4,405	8,438
Mutual Funds [Member] | Other assets, net [Member]
Financial assets at fair value
Financial Assets, Fair Value related to mutual fund	41,155	39,564
Mutual Funds [Member] | Level 1 [Member] | Other assets, net [Member]
Financial assets at fair value
Financial Assets, Fair Value related to mutual fund	41,155	39,564
Mutual Funds [Member] | Level 2 [Member] | Other assets, net [Member]
Financial assets at fair value
Financial Assets, Fair Value related to mutual fund
Mutual Funds [Member] | Level 3 [Member] | Other assets, net [Member]
Financial assets at fair value
Financial Assets, Fair Value related to mutual fund
Mutual Funds [Member] | Carrying Value [Member] | Other assets, net [Member]
Financial assets at fair value
Financial Assets, Fair Value related to mutual fund	41,155	39,564
Time Deposits [Member] | Short-term Investments [Member]
Financial assets at fair value
Financial Assets, Fair Value	1,357	32,210
Time Deposits [Member] | Level 1 [Member] | Short-term Investments [Member]
Financial assets at fair value
Financial Assets, Fair Value	1,357	32,210
Time Deposits [Member] | Level 2 [Member] | Short-term Investments [Member]
Financial assets at fair value
Financial Assets, Fair Value
Time Deposits [Member] | Level 3 [Member] | Short-term Investments [Member]
Financial assets at fair value
Financial Assets, Fair Value
Time Deposits [Member] | Carrying Value [Member] | Short-term Investments [Member]
Financial assets at fair value
Financial Assets, Fair Value	1,357	32,210
Interest rate swaps [Member] | Fair Value Hedging [Member] | Other assets, net [Member]
Financial assets at fair value
Derivative Assets, Fair Value		7,905
Interest rate swaps [Member] | Fair Value Hedging [Member] | Level 1 [Member] | Other assets, net [Member]
Financial assets at fair value
Derivative Assets, Fair Value
Interest rate swaps [Member] | Fair Value Hedging [Member] | Level 2 [Member] | Other assets, net [Member]
Financial assets at fair value
Derivative Assets, Fair Value		7,905
Interest rate swaps [Member] | Fair Value Hedging [Member] | Level 3 [Member] | Other assets, net [Member]
Financial assets at fair value
Derivative Assets, Fair Value
Interest rate swaps [Member] | Fair Value Hedging [Member] | Carrying Value [Member] | Other assets, net [Member]
Financial assets at fair value
Derivative Assets, Fair Value		7,905
Precious Metal Forward Contracts [Member] | Cash Flow Hedging [Member] | Prepaid expenses and other current assets [Member]
Financial assets at fair value
Derivative Assets, Fair Value	23	2,322
Precious Metal Forward Contracts [Member] | Cash Flow Hedging [Member] | Accounts payable and accrued liabilities [Member]
Financial liabilities at fair value
Derivative liabilities, Fair Value	3,946	146
Precious Metal Forward Contracts [Member] | Cash Flow Hedging [Member] | Level 1 [Member] | Prepaid expenses and other current assets [Member]
Financial assets at fair value
Derivative Assets, Fair Value
Precious Metal Forward Contracts [Member] | Cash Flow Hedging [Member] | Level 1 [Member] | Accounts payable and accrued liabilities [Member]
Financial liabilities at fair value
Derivative liabilities, Fair Value
Precious Metal Forward Contracts [Member] | Cash Flow Hedging [Member] | Level 2 [Member] | Prepaid expenses and other current assets [Member]
Financial assets at fair value
Derivative Assets, Fair Value	23	2,322
Precious Metal Forward Contracts [Member] | Cash Flow Hedging [Member] | Level 2 [Member] | Accounts payable and accrued liabilities [Member]
Financial liabilities at fair value
Derivative liabilities, Fair Value	3,946	146
Precious Metal Forward Contracts [Member] | Cash Flow Hedging [Member] | Level 3 [Member] | Prepaid expenses and other current assets [Member]
Financial assets at fair value
Derivative Assets, Fair Value
Precious Metal Forward Contracts [Member] | Cash Flow Hedging [Member] | Level 3 [Member] | Accounts payable and accrued liabilities [Member]
Financial liabilities at fair value
Derivative liabilities, Fair Value
Precious Metal Forward Contracts [Member] | Cash Flow Hedging [Member] | Carrying Value [Member] | Prepaid expenses and other current assets [Member]
Financial assets at fair value
Derivative Assets, Fair Value	23	2,322
Precious Metal Forward Contracts [Member] | Cash Flow Hedging [Member] | Carrying Value [Member] | Accounts payable and accrued liabilities [Member]
Financial liabilities at fair value
Derivative liabilities, Fair Value	3,946	146
Foreign exchange forward contracts [Member] | Cash Flow Hedging [Member] | Prepaid expenses and other current assets [Member]
Financial assets at fair value
Derivative Assets, Fair Value	1,414
Foreign exchange forward contracts [Member] | Cash Flow Hedging [Member] | Accounts payable and accrued liabilities [Member]
Financial liabilities at fair value
Derivative liabilities, Fair Value	382	8,258
Foreign exchange forward contracts [Member] | Cash Flow Hedging [Member] | Level 1 [Member] | Prepaid expenses and other current assets [Member]
Financial assets at fair value
Derivative Assets, Fair Value
Foreign exchange forward contracts [Member] | Cash Flow Hedging [Member] | Level 1 [Member] | Accounts payable and accrued liabilities [Member]
Financial liabilities at fair value
Derivative liabilities, Fair Value
Foreign exchange forward contracts [Member] | Cash Flow Hedging [Member] | Level 2 [Member] | Prepaid expenses and other current assets [Member]
Financial assets at fair value
Derivative Assets, Fair Value	1,414
Foreign exchange forward contracts [Member] | Cash Flow Hedging [Member] | Level 2 [Member] | Accounts payable and accrued liabilities [Member]
Financial liabilities at fair value
Derivative liabilities, Fair Value	382	8,258
Foreign exchange forward contracts [Member] | Cash Flow Hedging [Member] | Level 3 [Member] | Prepaid expenses and other current assets [Member]
Financial assets at fair value
Derivative Assets, Fair Value
Foreign exchange forward contracts [Member] | Cash Flow Hedging [Member] | Level 3 [Member] | Accounts payable and accrued liabilities [Member]
Financial liabilities at fair value
Derivative liabilities, Fair Value
Foreign exchange forward contracts [Member] | Cash Flow Hedging [Member] | Carrying Value [Member] | Prepaid expenses and other current assets [Member]
Financial assets at fair value
Derivative Assets, Fair Value	1,414
Foreign exchange forward contracts [Member] | Cash Flow Hedging [Member] | Carrying Value [Member] | Accounts payable and accrued liabilities [Member]
Financial liabilities at fair value
Derivative liabilities, Fair Value	382	8,258
Foreign exchange forward contracts [Member] | Non Designated [Member] | Prepaid expenses and other current assets [Member]
Financial assets at fair value
Derivative Assets, Fair Value	423	75
Foreign exchange forward contracts [Member] | Non Designated [Member] | Accounts payable and accrued liabilities [Member]
Financial liabilities at fair value
Derivative liabilities, Fair Value	77	34
Foreign exchange forward contracts [Member] | Non Designated [Member] | Level 1 [Member] | Prepaid expenses and other current assets [Member]
Financial assets at fair value
Derivative Assets, Fair Value
Foreign exchange forward contracts [Member] | Non Designated [Member] | Level 1 [Member] | Accounts payable and accrued liabilities [Member]
Financial liabilities at fair value
Derivative liabilities, Fair Value
Foreign exchange forward contracts [Member] | Non Designated [Member] | Level 2 [Member] | Prepaid expenses and other current assets [Member]
Financial assets at fair value
Derivative Assets, Fair Value	423	75
Foreign exchange forward contracts [Member] | Non Designated [Member] | Level 2 [Member] | Accounts payable and accrued liabilities [Member]
Financial liabilities at fair value
Derivative liabilities, Fair Value	77	34
Foreign exchange forward contracts [Member] | Non Designated [Member] | Level 3 [Member] | Prepaid expenses and other current assets [Member]
Financial assets at fair value
Derivative Assets, Fair Value
Foreign exchange forward contracts [Member] | Non Designated [Member] | Level 3 [Member] | Accounts payable and accrued liabilities [Member]
Financial liabilities at fair value
Derivative liabilities, Fair Value
Foreign exchange forward contracts [Member] | Non Designated [Member] | Carrying Value [Member] | Prepaid expenses and other current assets [Member]
Financial assets at fair value
Derivative Assets, Fair Value	423	75
Foreign exchange forward contracts [Member] | Non Designated [Member] | Carrying Value [Member] | Accounts payable and accrued liabilities [Member]
Financial liabilities at fair value
Derivative liabilities, Fair Value	77	34
Put option contracts [Member] | Cash Flow Hedging [Member] | Prepaid expenses and other current assets [Member]
Financial assets at fair value
Derivative Assets, Fair Value	152
Put option contracts [Member] | Cash Flow Hedging [Member] | Level 1 [Member] | Prepaid expenses and other current assets [Member]
Financial assets at fair value
Derivative Assets, Fair Value
Put option contracts [Member] | Cash Flow Hedging [Member] | Level 2 [Member] | Prepaid expenses and other current assets [Member]
Financial assets at fair value
Derivative Assets, Fair Value	152
Put option contracts [Member] | Cash Flow Hedging [Member] | Level 3 [Member] | Prepaid expenses and other current assets [Member]
Financial assets at fair value
Derivative Assets, Fair Value
Put option contracts [Member] | Cash Flow Hedging [Member] | Carrying Value [Member] | Prepaid expenses and other current assets [Member]
Financial assets at fair value
Derivative Assets, Fair Value	$ 152