Summary of Business and Significant Accounting Policies - Revenues by Geographical Region (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Oct. 31, 2014	Oct. 31, 2013	Oct. 31, 2014	Oct. 31, 2013
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues by geographical region	$ 1,383,655	$ 1,076,034	$ 3,928,978	$ 2,925,761
Reportable geographical components | Americas
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues by geographical region	995,331	769,400	2,812,654	2,079,043
Reportable geographical components | Europe
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues by geographical region	252,982	194,932	730,324	531,463
Reportable geographical components | Asia Pacific
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues by geographical region	$ 135,342	$ 111,702	$ 386,000	$ 315,255