Represents the minimum number of contracts entered by the entity per customer.

No definition available.

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

- Definition

Represents the number of members receiving behavioral healthcare management and other related services.

+ References

No definition available.

+ Details

Name:	mgln_NumberOfMembers
Namespace Prefix:	mgln_
Data Type:	xbrli:integerItemType
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=26872669&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_IowaContractsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MajorCustomersAxis=mgln_MaricopaCountyRegionalBehavioralHealthAuthorityMember
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_ConcentrationRiskByBenchmarkAxis=us-gaap_SalesRevenueServicesNetMember
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_CustomerBMember
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:

- Details

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

Summary of Significant Accounting Policies - Significant Customers (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2014 USD ($)	Jun. 30, 2014 USD ($)	Mar. 31, 2014 USD ($) item	Dec. 31, 2015 USD ($) item	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Significant customers
Revenues generated	$ 1,268,743	$ 1,190,082	$ 1,157,607	$ 980,968	$ 982,459	$ 923,170	$ 888,014	$ 966,475	$ 4,597,400	$ 3,760,118	$ 3,546,317
Iowa Contracts
Significant customers
Revenues generated									530,300	465,000	321,100
Maricopa County Regional Behavioral Health Authority
Significant customers
Number of members receiving behavioral healthcare management and other related services \| item								680,000
Revenues generated										216,600	755,000
Healthcare \| Customer A \| Service
Significant customers
Revenues generated									439,481	253,661	128,607
Pharmacy Management \| Customer B \| Service
Significant customers
Revenues generated									$ 130,200	123,812	133,724
Minimum number of contracts per customer \| item									1
Pharmacy Management \| Customer C \| Service
Significant customers
Revenues generated									$ 324,809	171,936
Pharmacy Management \| Customer D \| Service
Significant customers
Revenues generated										$ 2,612	$ 92,647