Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2020	Oct. 31, 2019
Income Tax Disclosure [Abstract]
Net income before (benefit from) provision for income taxes	$ 194,021	$ 2,530	$ 413,381	$ 11,817
(Benefit from) provision for income taxes	$ (4,621)	$ 319	$ 1,675	$ 1,851
Effective tax rate	(2.40%)	12.60%	0.40%	15.70%