STOCK-BASED COMPENSATION STOCK-BASED COMPENSATION - STOCK-BASED COMPENSATION - BY TYPE (Details) - USD ($)
$ in Thousands
3 Months Ended
Apr. 30, 2016
Apr. 30, 2015
Stock-Based Compensation Plans    
Stock-based compensation expense $ 15,340 $ 14,850
Equity Settled Awards    
Stock-Based Compensation Plans    
Stock-based compensation expense 15,312 14,791
Equity Settled Awards | Restricted stock units and restricted stock awards    
Stock-Based Compensation Plans    
Stock-based compensation expense 13,966 13,100
Equity Settled Awards | Stock Bonus Program and Bonus Share Program    
Stock-Based Compensation Plans    
Stock-based compensation expense 1,346 1,691
Liability Settled Awards | Phantom stock units (cash settled awards)    
Stock-Based Compensation Plans    
Stock-based compensation expense $ 28 $ 59