Property and Equipment - Additional Information (Detail) ft² in Thousands, $ in Thousands	3 Months Ended
	Apr. 30, 2017 USD ($)	Apr. 30, 2016 USD ($)	Jan. 31, 2017 USD ($)	Dec. 31, 2013 ft²
Property, Plant and Equipment [Line Items]
Depreciation and amortization expense	$ 88,100	$ 75,600
Fixed assets acquired under capital lease agreements	731,700		$ 729,000
Net rentable area (in square feet) | ft²				445
Property and equipment, gross	3,128,315		2,985,884
Financing obligation - leased facility, current	19,695		19,594
Financing obligation - leased facility	200,129		200,711
Expected financing obligation	317,018
Computers, equipment and software
Property, Plant and Equipment [Line Items]
Accumulated depreciation and amortization	409,000		386,900
Property and equipment, gross	1,503,140		1,440,986
Buildings and building improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	621,950		621,377
Construction costs capitalized
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 178,800		$ 178,800