Number of contracts.

No definition available.

Name:	mgln_NumberOfContracts
Namespace Prefix:	mgln_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of days required for a customer to have the right to terminate a contract for cause.

+ References

No definition available.

+ Details

Name:	mgln_TerminationClauseNumberOfDaysNoticeToTerminate
Namespace Prefix:	mgln_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the number of days required for a customer to have the right to terminate a contract without cause after January 1, 2014.

+ References

No definition available.

+ Details

Name:	mgln_TerminationClauseNumberOfDaysNoticeToTerminateWithoutCause
Namespace Prefix:	mgln_
Data Type:	xbrli:durationItemType
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_EntityWideRevenueMajorCustomerLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

+ Details

Name:	us-gaap_Revenues
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	us-gaap_MajorCustomersAxis=mgln_FloridaContractsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=mgln_HealthCareMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MajorCustomersAxis=mgln_CustomerAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MajorCustomersAxis=mgln_CustomerBMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=mgln_PharmacySolutionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MajorCustomersAxis=mgln_CustomerCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

General - Customers Exceeding Ten Percent of Consolidated Net Revenues (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($) contract	Jun. 30, 2017 USD ($)
Operating results by business segment
Revenues	$ 1,810,923	$ 1,419,139	$ 3,616,000	$ 2,724,762
Florida Contract
Operating results by business segment
Termination notice			1 day
Termination notice period without cause			30 days
Revenues			$ 307,900	300,100
Healthcare \| Customer A
Operating results by business segment
Revenues			356,573	79,247
Healthcare \| Customer B
Operating results by business segment
Revenues			$ 330,910
Healthcare \| Customer B \| Minimum
Operating results by business segment
Number of contracts \| contract			1
Pharmacy Management \| Customer C
Operating results by business segment
Revenues			$ 176,650	$ 184,364