Fair Value Of Financial Instruments (Details) (USD $)	3 Months Ended										6 Months Ended
	Apr. 30, 2013	Jul. 31, 2013 Senior Notes	Jan. 31, 2013 Senior Notes	Sep. 30, 2012 Senior Notes	Jul. 31, 2013 Fair Value, Measurements, Recurring	Jul. 31, 2013 Level 1 Senior Notes	Jul. 31, 2013 Level 2 Fair Value, Measurements, Recurring	Jan. 31, 2013 Level 2 Fair Value, Measurements, Recurring	Jul. 31, 2013 Fair Value, Inputs, Level 3 [Member] Fair Value, Measurements, Recurring	Jan. 31, 2013 Fair Value, Inputs, Level 3 [Member] Fair Value, Measurements, Recurring	Jul. 31, 2013 Selling, General and Administrative Expenses	Jul. 31, 2013 Other Expense
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency forward contracts, Assets							$ 12,250,000	$ 19,835,000
Foreign currency forward contracts, Liabilities							23,454,000	19,628,000
Acquisition-related contingent consideration									9,760,000	18,147,000
Adjustments to the fair value of acquisition-related contingent consideration											400,000	300,000
Deferred compensation plan assets, fair value disclosure					37,000,000
Deferred compensation liability, fair value disclosure					33,400,000
Convertible senior debentures, face value		350,000,000	350,000,000	350,000,000
Convertible debt, fair value disclosures						358,800,000
Payments for Previous Acquisition	$ 8,700,000