Shareholders' Equity | Components of AOCI (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2019	Oct. 31, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss) balance	$ (28,501)	$ 97,985	$ 43,786	$ 288,292
Other comprehensive income (loss), before reclassification	33,330	(91,430)	(38,870)	(276,664)
Reclassification of (gain) loss form AOCI into income	(55)	0	(142)	(5,073)
Accumulated other comprehensive income (loss) balance	4,774	6,555	4,774	6,555
Foreign currency translation adjustment, net of taxes
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss) balance	(28,559)	97,985	43,786	288,292
Other comprehensive income (loss), before reclassification	33,255	(91,430)	(39,090)	(276,664)
Reclassification of (gain) loss form AOCI into income	0	0	0	(5,073)
Accumulated other comprehensive income (loss) balance	4,696	6,555	4,696	6,555
Unrealized gains (losses) on cash flow hedges, net of taxes
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss) balance	58	0	0	0
Other comprehensive income (loss), before reclassification	75	0	220	0
Reclassification of (gain) loss form AOCI into income	(55)	0	(142)	0
Accumulated other comprehensive income (loss) balance	$ 78	$ 0	$ 78	$ 0