Long-term Debt - Financial Covenants (Details) - Credit Agreement	9 Months Ended
Sep. 30, 2016 USD ($) quarter
Debt Instrument [Line Items]
Consolidated EBITDA	1.25
Consolidated Net Income	$ 0
Facility Capital Expenditures	$ 30,000,000
Number of consecutive quarters for EBITDA to fixed charges ratio covenants \| quarter	4
Through March 31, 2017
Debt Instrument [Line Items]
Consolidated Total Leverage Ratio	4.5
April 1, 2017 through June 30, 2017
Debt Instrument [Line Items]
Consolidated Total Leverage Ratio	4.0
July 1, 2017 through December 31, 2017
Debt Instrument [Line Items]
Consolidated Total Leverage Ratio	3.75
January 1, 2018 through March 31, 2018
Debt Instrument [Line Items]
Consolidated Total Leverage Ratio	3.5
April 1, 2018 and thereafter
Debt Instrument [Line Items]
Consolidated Total Leverage Ratio	3.25

Line of Credit Facility, Covenant Terms, Consolidated EBITDA to Fixed Charges Ratio, Minimum

No definition available.

Name:	mmsi_LineOfCreditFacilityCovenantTermsConsolidatedEbitdaToFixedChargesRatioMinimum
Namespace Prefix:	mmsi_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Line of Credit Facility, Covenant Terms, Consolidated EBITDA to Fixed Charges Ratio, Number of Consecutive Quarters

+ References

No definition available.

+ Details

Name:	mmsi_LineOfCreditFacilityCovenantTermsConsolidatedEbitdaToFixedChargesRatioNumberOfConsecutiveQuarters
Namespace Prefix:	mmsi_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Line of Credit Facility, Covenant Terms, Facility Capital Expenditures, Next Twelve Months, Maximum

+ References

No definition available.

+ Details

Name:	mmsi_LineOfCreditFacilityCovenantTermsFacilityCapitalExpendituresNextTwelveMonthsMaximum
Namespace Prefix:	mmsi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Line of Credit Facility, Covenant Terms, Consolidated Net Income, Minimum

+ References

No definition available.

+ Details

Name:	mmsi_LineofCreditFacilityCovenantTermsConsolidatedNetIncomeMinimum
Namespace Prefix:	mmsi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Line of Credit Facility, Covenant Terms, Consolidated Total Leverage Ratio, Maximum

+ References

No definition available.

+ Details

Name:	mmsi_LineofCreditFacilityCovenantTermsConsolidatedTotalLeverageRatioMaximum
Namespace Prefix:	mmsi_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

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.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_DebtInstrumentAxis=mmsi_CreditAgreementMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	mmsi_DebtCovenantPeriodAxis=mmsi_ConsolidatedTotalLeverageRatioPeriodOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	mmsi_DebtCovenantPeriodAxis=mmsi_ConsolidatedTotalLeverageRatioPeriodTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	mmsi_DebtCovenantPeriodAxis=mmsi_ConsolidatedTotalLeverageRatioPeriodThreeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	mmsi_DebtCovenantPeriodAxis=mmsi_ConsolidatedTotalLeverageRatioPeriodFourMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	mmsi_DebtCovenantPeriodAxis=mmsi_ConsolidatedTotalLeverageRatioPeriodFiveandThereafterMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: