Fair Value Measurements (Details) - USD ($)	12 Months Ended
	Jan. 31, 2016	Jan. 31, 2015	Jan. 31, 2014	Sep. 30, 2012
Assets, Fair Value Disclosure [Abstract]
Disposal Group, Including Discontinued Operation, Assets, Current	$ 0	$ 101,706,000
Liabilities, Fair Value Disclosure [Abstract]
Loss on disposal of subsidiaries	699,000	1,330,000	$ 0
Senior Notes
Liabilities, Fair Value Disclosure [Abstract]
Convertible senior debentures, face value	350,000,000	350,000,000		$ 350,000,000
Level 1 | Senior Notes
Liabilities, Fair Value Disclosure [Abstract]
Convertible debt, fair value disclosures	359,600,000
Level 2 | Fair Value, Measurements, Recurring
Assets, Fair Value Disclosure [Abstract]
Foreign currency forward contracts	3,412,000	9,903,000
Liabilities, Fair Value Disclosure [Abstract]
Foreign currency forward contracts	2,274,000	5,411,000
Level 3 | Fair Value, Measurements, Recurring
Liabilities, Fair Value Disclosure [Abstract]
Business Combination, Contingent Consideration, Liability	$ 0	3,381,000
Assets, Total
Assets, Fair Value Disclosure [Abstract]
Disposal Group, Including Discontinued Operation, Assets, Current		$ 101,706,000