Summary of Significant Accounting Policies - Pronouncements not yet adopted (Details) $ in Millions	Apr. 02, 2018 USD ($)
Difference between Revenue Guidance in Effect before and after Topic 606 \| ASU 2014-09
Revenue, Initial Application Period Cumulative Effect Transition
Effect on revenue	$ 0.0

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

No definition available.

Name:	tess_RevenueFromContractWithCustomerExcludingAssessedTax
Namespace Prefix:	tess_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration