STOCK-BASED COMPENSATION - Schedule of Stock-Based Compensation Expense by Type of Award (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2021	Jul. 31, 2020	Jul. 31, 2021	Jul. 31, 2020
Stock-Based Compensation Plans
Stock-based compensation	$ 18,093	$ 13,329	$ 34,494	$ 24,007
Equity Settled Awards
Stock-Based Compensation Plans
Stock-based compensation	18,084	13,325	34,489	24,008
Equity Settled Awards | Restricted stock units and restricted stock awards
Stock-Based Compensation Plans
Stock-based compensation	15,984	10,040	30,237	21,296
Equity Settled Awards | Stock bonus program and bonus share program
Stock-Based Compensation Plans
Stock-based compensation	2,100	3,285	4,252	2,712
Cash Settled Awards | Phantom stock units (cash-settled awards)
Stock-Based Compensation Plans
Stock-based compensation	$ 9	$ 4	$ 5	$ (1)