STOCKHOLDERS' EQUITY STOCKHOLDERS' EQUITY - SCHEDULE OF ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2018	Jan. 31, 2017	Jan. 31, 2016
Class of Stock [Line Items]
Accumulated other comprehensive income (loss) - beginning balance	$ (154,856)	$ (116,194)
Other comprehensive (loss) income before reclassifications	57,817	(37,523)
Amounts reclassified out of accumulated other comprehensive income (loss)	6,421	1,139
Net other comprehensive income (loss)	51,396	(38,662)
Accumulated other comprehensive income (loss) - ending balance	(103,460)	(154,856)	$ (116,194)
Unrealized gains (losses) on available-for-sale investments
Class of Stock [Line Items]
Accumulated other comprehensive income (loss) - beginning balance	0	(110)
Other comprehensive (loss) income before reclassifications	0	110
Amounts reclassified out of accumulated other comprehensive income (loss)	0	0
Net other comprehensive income (loss)	0	110
Accumulated other comprehensive income (loss) - ending balance	0	0	(110)
Foreign currency translation adjustments
Class of Stock [Line Items]
Accumulated other comprehensive income (loss) - beginning balance	(156,063)	(114,213)
Other comprehensive (loss) income before reclassifications	49,291	(41,850)
Amounts reclassified out of accumulated other comprehensive income (loss)	0	0
Net other comprehensive income (loss)	49,291	(41,850)
Accumulated other comprehensive income (loss) - ending balance	(106,772)	(156,063)	(114,213)
Foreign Exchange Contract
Class of Stock [Line Items]
Amounts reclassified out of accumulated other comprehensive income (loss)	6,130	1,139	(7,113)
Foreign Exchange Contract | Unrealized gains (losses) on derivative financial instruments designated as hedges
Class of Stock [Line Items]
Accumulated other comprehensive income (loss) - beginning balance	575	(1,871)
Other comprehensive (loss) income before reclassifications	8,867	3,585
Amounts reclassified out of accumulated other comprehensive income (loss)	6,130	1,139
Net other comprehensive income (loss)	2,737	2,446
Accumulated other comprehensive income (loss) - ending balance	3,312	575	(1,871)
Interest Rate Swap
Class of Stock [Line Items]
Amounts reclassified out of accumulated other comprehensive income (loss)	291	0	0
Interest Rate Swap | Unrealized gains (losses) on derivative financial instruments designated as hedges
Class of Stock [Line Items]
Accumulated other comprehensive income (loss) - beginning balance	632	0
Other comprehensive (loss) income before reclassifications	(341)	632
Amounts reclassified out of accumulated other comprehensive income (loss)	291	0
Net other comprehensive income (loss)	(632)	632
Accumulated other comprehensive income (loss) - ending balance	$ 0	$ 632	$ 0