XML 77 R54.htm IDEA: XBRL DOCUMENT
v3.7.0.1

Loss Reserves - Delinquent Items (Details) $ in Millions | Mar. 31, 2017 USD ($) loan | Dec. 31, 2016 USD ($) loan | Mar. 31, 2016 loan | Dec. 31, 2015 loan
--- | --- | --- | --- | ---
Aging of the Primary Default Inventory [Abstract] |  |  |  |
3 months or less (in loans) | 9,184 | 12,194 | 10,120 |
3 months or less (as a percent) | 20.00% | 24.00% | 18.00% |
4 - 11 months (in loans) | 13,617 | 13,450 | 15,319 |
4 - 11 months (as a percent) | 30.00% | 27.00% | 28.00% |
12 months or more (in loans) | 22,548 | 24,638 | 30,151 |
12 months or more (as a percent) | 50.00% | 49.00% | 54.00% |
Total primary default inventory (in loans) | 45,349 | 50,282 | 55,590 | 62,633
Total primary default inventory (as a percent) | 100.00% | 100.00% | 100.00% |
Primary claims received inventory included in ending default inventory (in loans) | 1,390 | 1,385 | 2,267 |
Primary claims received inventory included in ending default inventory (as a percent) | 3.00% | 3.00% | 4.00% |
Percent of default inventory in default for more than 36 months (as a percent) | 48.00% | 47.00% | 49.00% |
Number of payments delinquent [Abstract] |  |  |  |
3 payments or less (in loans) | 15,692 | 18,419 | 16,864 |
3 payments or less (as a percent) | 35.00% | 36.00% | 30.00% |
4 - 11 payments (in loans) | 12,275 | 12,892 | 14,595 |
4 - 11 payments (as a percent) | 27.00% | 26.00% | 26.00% |
12 payments or more (in loans) | 17,382 | 18,971 | 24,131 |
12 payments or more (as a percent) | 38.00% | 38.00% | 44.00% |
Total primary default inventory (in loans) | 45,349 | 50,282 | 55,590 | 62,633
Total primary default inventory (as a percent) | 100.00% | 100.00% | 100.00% |
Pool insurance notice inventory (in number of loans) | 1,714 | 1,883 | 2,247 |
Premium refund liability, expected future rescissions | $ | $ 5 | $ 5 |  |

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

X
- Definition The number of loans in the primary default inventory that have been delinquent for twelve payments or more. + References No definition available. + Details
Name: | mtg_NumberOfPaymentsDelinquent12PaymentsOrMore
Namespace Prefix: | mtg_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition The percentage of loans in the primary default inventory that have been delinquent for twelve payments or more. + References No definition available. + Details
Name: | mtg_NumberOfPaymentsDelinquent12PaymentsOrMorePercentage
Namespace Prefix: | mtg_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The number of loans in the primary default inventory that have been delinquent for three payments or less. + References No definition available. + Details
Name: | mtg_NumberOfPaymentsDelinquent3PaymentsOrLess
Namespace Prefix: | mtg_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition The percentage of loans in the primary default inventory that have been delinquent for three payments or less. + References No definition available. + Details
Name: | mtg_NumberOfPaymentsDelinquent3PaymentsOrLessPercentage
Namespace Prefix: | mtg_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The number of loans in the primary default inventory that have been delinquent for at least four payments but no more than eleven payments. + References No definition available. + Details
Name: | mtg_NumberOfPaymentsDelinquent4To11Payments
Namespace Prefix: | mtg_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition The percentage of loans in the primary default inventory that have been delinquent for at least four payments but no more than eleven payments. + References No definition available. + Details
Name: | mtg_NumberOfPaymentsDelinquent4To11PaymentsPercentage
Namespace Prefix: | mtg_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

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

X
- Definition The number of loans included in the pool insurance notice inventory as of the end of the reporting period. + References No definition available. + Details
Name: | mtg_PoolInsuranceNoticeInventory
Namespace Prefix: | mtg_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition The carrying amount for the estimate of premiums to be refunded on expected future rescissions. + References No definition available. + Details
Name: | mtg_PremiumRefundLiabilityExpectedFutureRescissions
Namespace Prefix: | mtg_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The number of loans in the primary default inventory. + References No definition available. + Details
Name: | mtg_PrimaryDefaultInventory
Namespace Prefix: | mtg_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition The number of loans in the primary default inventory that are in the claims received inventory. + References No definition available. + Details
Name: | mtg_PrimaryDefaultInventoryClaimsReceivedInventory
Namespace Prefix: | mtg_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition The percentage of loans in the primary default inventory that are in the claims received inventory. + References No definition available. + Details
Name: | mtg_PrimaryDefaultInventoryClaimsReceivedInventoryPercentage
Namespace Prefix: | mtg_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The number of loans that have been in the primary default inventory for at least four months but no greater than eleven months as of the balance sheet date. + References No definition available. + Details
Name: | mtg_PrimaryDefaultInventoryFourToElevenMonths
Namespace Prefix: | mtg_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition The percentage of loans that have been in the primary default inventory for at least four months but no greater than eleven months as of the balance sheet date. + References No definition available. + Details
Name: | mtg_PrimaryDefaultInventoryFourToElevenMonthsPercentage
Namespace Prefix: | mtg_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The percentage of loans in the primary default inventory. + References No definition available. + Details
Name: | mtg_PrimaryDefaultInventoryPercentage
Namespace Prefix: | mtg_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The number of loans that have been in the primary default inventory for three months or less as of the balance sheet date. + References No definition available. + Details
Name: | mtg_PrimaryDefaultInventoryThreeMonthsOrLess
Namespace Prefix: | mtg_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition The percentage of loans that have been in the primary default inventory for three months or less as of the balance sheet date. + References No definition available. + Details
Name: | mtg_PrimaryDefaultInventoryThreeMonthsOrLessPercentage
Namespace Prefix: | mtg_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The number of loans that have been in the primary default inventory for twelve months or more as of the balance sheet date. + References No definition available. + Details
Name: | mtg_PrimaryDefaultInventoryTwelveMonthsOrMore
Namespace Prefix: | mtg_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Primary Default Inventory Twelve Months Or More, Percent Of Primary Default Inventory In Default For Twelve Months Or More In Default For More Than Thirty Six Consecutive Months + References No definition available. + Details
Name: | mtg_PrimaryDefaultInventoryTwelveMonthsOrMorePercentOfPrimaryDefaultInventoryInDefaultForTwelveMonthsOrMoreInDefaultForMoreThanThirtySixConsecutiveMonths
Namespace Prefix: | mtg_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The percentage of loans that have been in the primary default inventory for twelve months or more as of the balance sheet date. + References No definition available. + Details
Name: | mtg_PrimaryDefaultInventoryTwelveMonthsOrMorePercentage
Namespace Prefix: | mtg_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant