Inventories - Textuals (Details) - USD ($) $ in Millions	Jul. 31, 2020	Jan. 31, 2020	Jul. 31, 2019
Inventory [Line Items]
Inventory held on consignment	$ 6.3	$ 9.1	$ 3.9
Prepaid Expenses and Other Current Assets
Inventory [Line Items]
Inventory return asset	$ 15.1	$ 31.0	$ 24.8

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_InventoryLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration