XML 117 R86.htm IDEA: XBRL DOCUMENT
v3.19.3

Employee Benefit Plans - Additional Information (Detail) - USD ($) | 12 Months Ended
--- | ---
Sep. 27, 2019 | Sep. 28, 2018 | Sep. 29, 2017
Domestic Plan | Calender Year 2017 |  |  |
Employee Benefit Plan [Line Items] |  |  |
Discretionary matching contribution |  | $ 2,700,000 |
Domestic Plan | Calender Year 2018 |  |  |
Employee Benefit Plan [Line Items] |  |  |
Discretionary matching contribution | $ 2,600,000 |  |
Domestic Plan | Calender Year 2019 |  |  |
Employee Benefit Plan [Line Items] |  |  |
Discretionary matching contribution | 0 |  |
Domestic Plan | Calender Year 2016 |  |  |
Employee Benefit Plan [Line Items] |  |  |
Discretionary matching contribution |  |  | $ 2,400,000
Foreign Plan |  |  |
Employee Benefit Plan [Line Items] |  |  |
Discretionary matching contribution | $ 1,100,000 | $ 1,200,000 | $ 1,300,000

X
- Definition Employee Benefit Plan [Line Items] + References No definition available. + Details
Name: | mtsi_EmployeeBenefitPlanLineItems
Namespace Prefix: | mtsi_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of discretionary contributions made by an employer to a defined contribution plan. + References No definition available. + Details
Name: | us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | us-gaap_RetirementPlanTypeAxis=us-gaap_DomesticPlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanNameAxis=mtsi_CalenderYearTwoThousandSeventeenMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanNameAxis=mtsi_CalenderYearTwoThousandEighteenMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanNameAxis=mtsi_CalenderYearTwoThousandNineteenMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanNameAxis=mtsi_CalenderYearTwoThousandAndSixteenMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RetirementPlanTypeAxis=us-gaap_ForeignPlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |