Commitments and Contingencies (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2017	Sep. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
Legal Fees In Responding to Department Of Justice Inquiry	$ 2.1	$ 10.6

Legal Fees In Responding to Department Of Justice Inquiry

No definition available.

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