Business and Summary of Significant Accounting Policies - Accounts Receivable, Net (Details) - USD ($) $ in Millions	Jan. 31, 2020	Jan. 31, 2019
Accounting Policies [Abstract]
Trade accounts receivable	$ 716.1	$ 529.3
Less: Allowance for doubtful accounts	(4.9)	(4.9)
Product returns reserve	(0.5)	(0.3)
Partner programs and other obligations	(58.4)	(49.8)
Accounts receivable, net	$ 652.3	$ 474.3