XML 57 R39.htm IDEA: XBRL DOCUMENT v3.21.1

Reinsurance - Summary of Quota Reinsurance Arrangements (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Effects of Reinsurance [Line Items]
Ceded losses incurred	$ 8,410	$ 5,772
Quota Share Reinsurance Agreements, Excluding Captive Agreements
Effects of Reinsurance [Line Items]
Ceded premiums written and earned, net of profit commission	33,390	26,846
Ceded losses incurred	8,405	5,804
Ceding commissions	13,067	11,365
Profit commission	$ 31,944	$ 29,979

X

- Definition

Ceded Premiums Written and Earned, Net of Profit Commission

+ References

No definition available.

+ Details

Name:	mtg_CededPremiumsWrittenandEarnedNetofProfitCommission
Namespace Prefix:	mtg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Reinsurance Ceding Commission Earned

+ References

No definition available.

+ Details

Name:	mtg_ReinsuranceCedingCommissionEarned
Namespace Prefix:	mtg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

Reinsurance, Profit Commission

+ References

No definition available.

+ Details

Name:	mtg_ReinsuranceProfitCommission
Namespace Prefix:	mtg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

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

X

- Definition

Amount of reduction of provision for policy benefits and costs incurred for policies ceded.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 20
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=99397103&loc=d3e6811-158387

+ Details

Name:	us-gaap_ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountCeded
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Details

Name:	us-gaap_ReinsurancePolicyTypeAxis=mtg_QuotaShareReinsuranceAgreementsExcludingCaptivesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: