Business And Summary Of Significant Accounting Policies (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2018	Jul. 31, 2017	Jan. 31, 2018
Accounting Policies [Abstract]
Accounts receivable sold	$ 866.2		$ 866.2		$ 687.2
Discount fees on sale of accounts receivable	$ 3.7	$ 2.3	$ 6.3	$ 4.1

Accounts Receivable Sold to and Held by Financial Institutions

No definition available.

Name:	tecd_AccountsReceivableSoldToandHeldbyFinancialInstitutions
Namespace Prefix:	tecd_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant