Notes Payable - Additional Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended		12 Months Ended
	Jan. 31, 2013	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2014	Jul. 31, 2013
Line of Credit Facility [Line Items]
Repayment of borrowing on notes payable		$ 30,000	$ 112,472	$ (211,000)
Weighted average borrowing rate		1.3615%		1.3615%
Remaining borrowing capacity		291,000		291,000
Line of Credit Facility, Maximum Borrowing Capacity		441,000		441,000
Outstanding balance on credit facility		23,946		23,946	50,613
Proceeds from borrowing on notes payable	220,000	(3,187)	0
USD-denominated credit facility China [Member]
Line of Credit Facility [Line Items]
Remaining borrowing capacity		11,254		11,254
USD-Denominated Borrowing Credit Revolver [Member]
Line of Credit Facility [Line Items]
Notes Payable		39,000		39,000
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Outstanding balance on credit facility		$ 9,000		$ 9,000	$ 39,000