CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended
	Apr. 30, 2021	Apr. 30, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 227,531	$ 27,075
Other comprehensive (loss) income:
Unrealized (loss) gain on available-for-sale marketable securities, net of tax	(639)	1,078
Comprehensive income	$ 226,892	$ 28,153