SEGMENTS - Method of Overhead Allocation (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Jan. 31, 2020	Oct. 31, 2019	Jul. 31, 2019	Apr. 30, 2019	Jan. 31, 2019	Oct. 31, 2018	Jul. 31, 2018	Apr. 30, 2018	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 754,617	$ 1,128,403	$ 643,892	$ 633,552	$ 766,785	$ 1,072,982	$ 624,698	$ 611,743	$ 3,160,464	$ 3,076,208	$ 2,806,938
Long-Lived Assets	1,196,449				954,163				1,196,449	954,163	955,576
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									2,774,492	2,656,479	2,466,107
Long-Lived Assets	964,476				762,444				964,476	762,444	770,128
Non-United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									385,972	419,729	340,831
Long-Lived Assets	$ 231,973				$ 191,719				$ 231,973	$ 191,719	$ 185,448