Derivative Instruments and Hedging Activities (Net Gains (Losses) Recognized in Income for Derivative Contracts) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Jun. 30, 2018	Jul. 01, 2017	Jun. 30, 2018	Jul. 01, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Net gain (loss) recognized in other income (expense), net	$ 981	$ (680)	$ (46)	$ (691)

The amount of net gains or losses on a cash flow hedge reclassified in the period to other (expense) income from accumulated other comprehensive income.

No definition available.

Name:	mtsc_CashFlowHedgeGainLossReclassifiedNetLossGainRecognizedInOtherExpenseIncomeNet
Namespace Prefix:	mtsc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration