Other Income (Expense), Net - Other Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2019	Jul. 31, 2018
Other Income and Expenses [Abstract]
Interest income	$ 6,772	$ 4,783	$ 13,606	$ 6,654
Interest expense	(6,981)	(6,615)	(13,648)	(8,113)
Foreign currency transactions losses	(443)	(2,273)	(2,426)	(4,407)
Other income	0	73	0	835
Total other income (expense), net	$ (652)	$ (4,032)	$ (2,468)	$ (5,031)