Commitments - Additional Information (Detail) (USD $)	0 Months Ended
	Apr. 10, 2014 sqft	Oct. 31, 2014	Jan. 31, 2014
Other Commitments [Line Items]
Financing obligation, building in progress-leased facility		$ 102,975,000	$ 40,171,000
Area leased	714,000
Future minimum lease payments due	560,000,000	2,218,903,000
Lease term	15 years 6 months
Letter of Credit
Other Commitments [Line Items]
Value of outstanding letters of credit		$ 64,300,000