Employee Stock Purchase Plan Stock Options and Warrants - Long Term Incentive Plans (Details) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014
2006 Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	447
Employee Stock Purchase Plan Qualified
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	205
Share Based Compensation Arrangement Employee Stock Purchase Plan Percentage of Market Price Purchase Date	95.00%
Employee Stock Purchase Plan Non Qualified
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	51
Stock Options \| 2006 Incentive Plan \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Stock Option Contractual Life	7 years
Stock Options \| 2006 Incentive Plan \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	5 years
Stock Option Contractual Life	10 years
Performance Shares \| 2006 Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	1 year

Share Based Compensation Arragement Employee Stock Purchase Plan, Percentage of Market Price. Purchase Date

No definition available.

Name:	mmsi_ShareBasedCompensationArrangementEmployeeStockPurchasePlanPercentageofMarketPricePurchaseDate
Namespace Prefix:	mmsi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)(2)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Details

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

- Definition

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_EmployeeStockOptionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_PerformanceSharesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PlanNameAxis=mmsi_EmployeeStockPurchasePlanNonQualifiedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PlanNameAxis=mmsi_EmployeeStockPurchasePlanQualifiedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PlanNameAxis=mmsi_LongTermIncentivePlan2006Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: