General - Leases - Maturity Dates (Details) $ in Thousands	Sep. 30, 2020 USD ($)
Leases
2020	$ 4,106
2021	14,417
2022	13,460
2023	9,815
2024	8,190
2025 and beyond	2,891
Total lease payments	$ 52,879

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 fifth fiscal year following latest fiscal year.

+ References

No definition available.

+ Details

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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 fifth fiscal year following latest fiscal year.

+ References

No definition available.

+ Details

Name:	mgln_LeaseLiabilityPaymentsDueYearFive
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.

+ References

No definition available.

+ Details

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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.

+ References

No definition available.

+ Details

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.

+ References

No definition available.

+ Details

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.

+ References

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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