v3.7.0.1
Accounting Standards and Significant Accounting Policies - Recently Adopted Accounting Pronouncements (Details) - USD ($)
$ in Millions
3 Months Ended
Feb. 01, 2017
Apr. 30, 2017
Apr. 30, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]      
Amortization period, deferred commissions   5 years  
Excess tax benefit $ 448.0    
Accounting Standards Update 2014-09      
New Accounting Pronouncements or Change in Accounting Principle [Line Items]      
Subscription contract period   3 years  
Accounting Standards Update 2016-09      
New Accounting Pronouncements or Change in Accounting Principle [Line Items]      
Deferred tax asset, valuation allowance 447.8    
Deferred income tax assets, net 0.2    
Accounting Standards Update 2016-18      
New Accounting Pronouncements or Change in Accounting Principle [Line Items]      
Cash, cash equivalents and restricted cash increase (decrease)     $ 1.0
Retained Earnings | Accounting Standards Update 2016-09      
New Accounting Pronouncements or Change in Accounting Principle [Line Items]      
Cumulative effect of new accounting principle in period of adoption $ 0.2    
Minimum | Accounting Standards Update 2014-09      
New Accounting Pronouncements or Change in Accounting Principle [Line Items]      
Amortization period, deferred commissions   3 years  
Maximum | Accounting Standards Update 2014-09      
New Accounting Pronouncements or Change in Accounting Principle [Line Items]      
Amortization period, deferred commissions   5 years