General - Leases - Maturity Dates (Details) $ in Thousands	Sep. 30, 2021 USD ($)
Leases
2021	$ 4,334
2022	15,795
2023	13,178
2024	11,392
2025	6,085
2026 beyond	6,171
Total lease payments	$ 56,955

Amount of lessee's undiscounted obligation for lease payments for operating and finance leases.

No definition available.

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- Definition

Amount of lessee's undiscounted obligation for lease payments for operating and finance lease, due after fourth fiscal year following latest fiscal year.

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No definition available.

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- Definition

Lease Liability, Payments, Due Next Twelve Months

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No definition available.

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

- Definition

Amount of lessee's undiscounted obligation for lease payments for operating and finance lease, due in fourth fiscal year following latest fiscal year.

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No definition available.

+ Details

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

- Definition

Amount of lessee's undiscounted obligation for lease payments for operating and finance lease, due in third fiscal year following latest fiscal year.

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No definition available.

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

- Definition

Amount of lessee's undiscounted obligation for lease payments for operating and finance lease, due in second fiscal year following latest fiscal year.

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No definition available.

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

- Definition

Amount of lessee's undiscounted obligation for lease payments for operating and finance lease, due in remainder of fiscal year following latest fiscal year ended.

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No definition available.

+ Details

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

- References

No definition available.

+ Details

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Period Type:	duration