The stated interest rate on letters of credit issued under the Revolving Loan Commitment.

No definition available.

Name:	mgln_LettersOfCreditIssuedInterestRateStatedPercentage
Namespace Prefix:	mgln_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The maximum amount of borrowing capacity under a line of credit that is available for the issuance of letters of credit.

+ References

No definition available.

+ Details

Name:	mgln_LineOfCreditFacilityCapacityAvailableForLettersOfCreditMaximum
Namespace Prefix:	mgln_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The sublimit within the overall line of credit capacity that is available for revolving loans.

+ References

No definition available.

+ Details

Name:	mgln_LineOfCreditFacilityCapacitySublimitAvailableForRevolvingLoansMaximum
Namespace Prefix:	mgln_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.

+ References

No definition available.

+ Details

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

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

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

- Details

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

- Definition

The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

+ References

No definition available.

+ Details

Name:	us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

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

General (Details 7) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Dec. 31, 2011	Dec. 09, 2011
Credit Facility
Maximum available for the issuance of letters of credit			$ 230.0
Sublimit on the amount of revolving loans			70.0
Interest rate on letters of credit issued (as a percent)	1.875%
Commitment commission (as a percent)	0.375%
Long Term Debt and Capital Lease Obligations
Letters of credit outstanding	$ 43.9	$ 68.1
U.S. dollar denominated loans
Interest rate on Revolving Loan borrowings
Borrowing margin (as a percent)	1.00%
Base interest rate (as a percent)	The higher of the prime rate, one-half of one percent in excess of the overnight "federal funds" rate or the Eurodollar rate for one month plus 1.00%
Eurodollar denominated loans
Interest rate on Revolving Loan borrowings
Borrowing margin (as a percent)	2.00%
Base interest rate (as a percent)	Eurodollar rate