XML 69 R46.htm IDEA: XBRL DOCUMENT
v3.7.0.1

Fair Value Measurements (Details) - USD ($) $ in Thousands | 3 Months Ended |
--- | --- | ---
Mar. 31, 2017 | Dec. 31, 2016
Fair Value Disclosures [Abstract] |  |
State premium tax credit investments, average maturity (in years) | 2 years |
Annual average discount rate (as a percent) | 7.10% |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
U.S. Treasury securities and obligations of U.S. government corporations and agencies | $ 60,818 | $ 73,530
Obligations of U.S. states and political subdivisions | 2,168,450 | 2,143,016
Corporate debt securities | 1,747,340 | 1,743,910
ABS | 37,117 | 59,565
RMBS | 212,909 | 224,209
CMBS | 294,117 | 319,817
CLOs | 121,368 | 121,175
Total debt securities | 4,642,119 | 4,685,222
Equity securities | 7,162 | 7,128
Total investment portfolio | 4,649,281 | 4,692,350
Real estate acquired | 10,730 | 11,748
Quoted Prices in Active Markets for Identical Assets (Level 1) |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
U.S. Treasury securities and obligations of U.S. government corporations and agencies | 12,431 | 30,690
Obligations of U.S. states and political subdivisions | 0 | 0
Corporate debt securities | 0 | 0
ABS | 0 | 0
RMBS | 0 | 0
CMBS | 0 | 0
CLOs | 0 | 0
Total debt securities | 12,431 | 30,690
Equity securities | 2,894 | 2,860
Total investment portfolio | 15,325 | 33,550
Real estate acquired | 0 | 0
Significant Other Observable Inputs (Level 2) |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
U.S. Treasury securities and obligations of U.S. government corporations and agencies | 48,387 | 42,840
Obligations of U.S. states and political subdivisions | 2,167,767 | 2,142,325
Corporate debt securities | 1,747,340 | 1,743,910
ABS | 37,117 | 59,565
RMBS | 212,909 | 224,209
CMBS | 294,117 | 319,817
CLOs | 121,368 | 121,175
Total debt securities | 4,629,005 | 4,653,841
Equity securities |  | 0
Total investment portfolio | 4,629,005 | 4,653,841
Real estate acquired | 0 | 0
Significant Unobservable Inputs (Level 3) |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |
U.S. Treasury securities and obligations of U.S. government corporations and agencies | 0 | 0
Obligations of U.S. states and political subdivisions | 683 | 691
Corporate debt securities | 0 | 0
ABS | 0 | 0
RMBS | 0 | 0
CMBS | 0 | 0
CLOs | 0 | 0
Total debt securities | 683 | 691
Equity securities | 4,268 | 4,268
Total investment portfolio | 4,951 | 4,959
Real estate acquired | $ 10,730 | $ 11,748

X
- Definition The fair value disclosure of Asset-backed securities as of the Balance sheet date. + References No definition available. + Details
Name: | mtg_AssetBackedSecuritiesFairValueDisclosure
Namespace Prefix: | mtg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The fair value disclosure of Collateralized loan obligations as of the Balance sheet date. + References No definition available. + Details
Name: | mtg_CollateralizedLoanObligationsFairValueDisclosure
Namespace Prefix: | mtg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The fair value disclosure of Commercial mortgage-backed securities as of the Balance sheet date. + References No definition available. + Details
Name: | mtg_CommercialMortgageBackedSecuritiesFairValueDisclosure
Namespace Prefix: | mtg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The fair value disclosure of Corporate debt securities as of the Balance sheet date. + References No definition available. + Details
Name: | mtg_CorporateDebtSecuritiesFairValueDisclosure
Namespace Prefix: | mtg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The fair value disclosure of Equity securities as of the Balance sheet date. + References No definition available. + Details
Name: | mtg_EquitySecurities
Namespace Prefix: | mtg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This element represents annual average discount rate used for fair value of state premium tax credit investments. + References No definition available. + Details
Name: | mtg_FairValueAnnualAverageDiscountRate
Namespace Prefix: | mtg_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The fair value disclosure of Obligations of U.S. states and political subdivisions as of the Balance sheet date. + References No definition available. + Details
Name: | mtg_ObligationsOfUSStatesAndPoliticalSubdivisionsFairValueDisclosure
Namespace Prefix: | mtg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The fair value disclosure of Residential mortgage-backed securities as of the Balance sheet date. + References No definition available. + Details
Name: | mtg_ResidentialMortgageBackedSecuritiesFairValueDisclosure
Namespace Prefix: | mtg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This element represents state premium tax credit investments, average maturity. + References No definition available. + Details
Name: | mtg_StatePremiumTaxCreditInvestmentsAverageMaturity
Namespace Prefix: | mtg_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition The fair value disclosure of Total debt securities as of the Balance sheet date. + References No definition available. + Details
Name: | mtg_TotalDebtSecuritiesFairValueDisclosure
Namespace Prefix: | mtg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The fair value disclosure of U.S. Treasury securities and obligations of U.S. government corporations and agencies as of the Balance sheet date. + References No definition available. + Details
Name: | mtg_USTreasurySecuritiesAndObligationsOfUSGovernmentCorporationsAndAgenciesFairValueDisclosure
Namespace Prefix: | mtg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 25 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=51813488&loc=d3e22054-111558 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27232-111563 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=49167202&loc=d3e26610-111562 + Details
Name: | us-gaap_AvailableForSaleSecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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

X
- References No definition available. + Details
Name: | us-gaap_FairValueDisclosuresAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Fair value portion of other assets. + References No definition available. + Details
Name: | us-gaap_OtherAssetsFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |