Trade and other receivables - Orbital receivables (Details) $ in Millions	3 Months Ended	12 Months Ended
Mar. 31, 2021 USD ($) customer	Dec. 31, 2020 USD ($) customer
Trade and other receivables
Reduction in outstanding receivables, final milestone	$ 15
Reduction in outstanding receivables, expected orbital payments	14
Orbital receivables, net	339	$ 361
Changes in allowance for expected credit losses related to non-current orbital receivables
Allowance at the beginning of the period	(49)
Allowance at the end of the period	$ (49)	$ (49)
Accounts Receivable \| Credit Concentration Risk
Trade and other receivables
Number of customers \| customer	14	14
Accounts Receivable \| Credit Concentration Risk \| Largest Customer
Trade and other receivables
Concentration risk, percentage	22.00%	19.00%

The amount of increase (decrease) during the reporting period in the orbital receivables for expected orbital payments.

No definition available.

Name:	maxr_IncreaseDecreaseInOutstandingReceivablesForExpectedOrbitalPayments
Namespace Prefix:	maxr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The amount of increase (decrease) during the reporting period in the orbital receivables for expected orbital payments.

+ References

No definition available.

+ Details

Name:	maxr_IncreaseDecreaseInOutstandingReceivablesForFinalMilestone
Namespace Prefix:	maxr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents the number of customers.

+ References

No definition available.

+ Details

Name:	maxr_NumberOfCustomers
Namespace Prefix:	maxr_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of non current portion of orbital receivables.

+ References

No definition available.

+ Details

Name:	maxr_OrbitalReceivablesNoncurrent
Namespace Prefix:	maxr_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

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

- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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+ Details

Name:	us-gaap_ConcentrationRiskPercentage1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
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Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
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-Publisher FASB
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+ Details

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

- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

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

- Details

Name:	us-gaap_ConcentrationRiskByBenchmarkAxis=us-gaap_AccountsReceivableMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConcentrationRiskByTypeAxis=us-gaap_CreditConcentrationRiskMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_MajorCustomersAxis=maxr_LargestCustomerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: