Fair Value Measurements (Details) - USD ($) $ in Thousands	Apr. 30, 2016	Jan. 31, 2016	Sep. 21, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Life Insurance, Corporate or Bank Owned, Amount	$ 33,000	$ 30,200
Deferred Compensation Liability, Current and Noncurrent	33,000	30,500
Fair Value, Measurements, Recurring | Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Foreign currency forward contracts - Assets	2,115	3,412
Foreign currency forward contracts - Liabilities	3,997	2,274
Senior Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Instrument, Face Amount			$ 350,000
Debt Instrument, Interest Rate, Stated Percentage			3.75%
Senior Notes [Member] | Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Debt Instrument, Fair Value Disclosure	$ 356,200	$ 359,600