v3.26.1
Long-Term Debt (Details) - USD ($)
$ in Millions
6 Months Ended
Jul. 31, 2026
Jan. 31, 2026
Long-Term Debt    
Letters of credit outstanding $ 0.2 $ 0.2
Revolving credit facility | Senior secured credit facility    
Long-Term Debt    
Maturity term (year) 5 years  
Long-term line of credit drawn amount $ 0.0  
Available for use 350.0  
Revolving credit facility | Senior secured credit facility | Minimum    
Long-Term Debt    
Line of credit facility 350.0  
Revolving credit facility | Senior secured credit facility | Maximum    
Long-Term Debt    
Line of credit facility $ 500.0  
Senior secured credit facility | Minimum    
Long-Term Debt    
Interest rates under the revolving operating portion 0.00%  
Debt Instrument, Variable Interest Rate, Type [Extensible Enumeration] dsgx:CanadaOrUsPrimeRateCorraOrSofrMember  
Percentage of undrawn amounts (in percentage) 0.20%  
Senior secured credit facility | Maximum    
Long-Term Debt    
Interest rates under the revolving operating portion 2.50%  
Debt Instrument, Variable Interest Rate, Type [Extensible Enumeration] dsgx:CanadaOrUsPrimeRateCorraOrSofrMember  
Percentage of undrawn amounts (in percentage) 0.40%