XML 92 R61.htm IDEA: XBRL DOCUMENT
v3.6.0.2

Reinsurance - Summary of Quota Share Reinsurance Agreements (Details) - USD ($) $ in Thousands |  | 3 Months Ended | 12 Months Ended
--- | --- | --- | ---
Jul. 01, 2015 | Dec. 31, 2016 | Sep. 30, 2016 | Jun. 30, 2016 | Mar. 31, 2016 | Dec. 31, 2015 | Sep. 30, 2015 | Jun. 30, 2015 | Mar. 31, 2015 | Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014
Premiums Earned, Net [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Premiums earned, direct |  |  |  |  |  |  |  |  |  | $ 1,058,545 | $ 997,892 | $ 950,973
Premiums earned, assumed |  |  |  |  |  |  |  |  |  | 662 | 1,178 | 1,653
Premiums earned, ceded |  |  |  |  |  |  |  |  |  | (133,981) | (102,848) | (108,255)
Net premiums earned |  | $ 235,053 | $ 237,376 | $ 231,456 | $ 221,341 | $ 226,192 | $ 239,234 | $ 213,508 | $ 217,288 | 925,226 | 896,222 | 844,371
Policyholder Benefits and Claims Incurred, Net [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Losses incurred, direct |  |  |  |  |  |  |  |  |  | 273,207 | 369,680 | 524,051
Losses incurred, assumed |  |  |  |  |  |  |  |  |  | 1,138 | 1,552 | 2,012
Losses incurred, ceded |  |  |  |  |  |  |  |  |  | (34,188) | (27,685) | (29,986)
Net losses incurred |  | $ 47,658 | $ 60,897 | $ 46,590 | $ 85,012 | $ 95,066 | 76,458 | $ 90,238 | $ 81,785 | 240,157 | 343,547 | 496,077
Ceded premiums written, net of profit commission |  |  |  |  |  |  |  |  |  | 133,885 | 55,391 | 119,634
Ceded premiums earned, net of profit commission |  |  |  |  |  |  |  |  |  | 133,981 | 102,848 | 108,255
Ceded losses incurred |  |  |  |  |  |  |  |  |  | 34,188 | 27,685 | 29,986
Quota Share Reinsurance Agreement, 2015 |  |  |  |  |  |  |  |  |  |  |  |
Premiums Earned, Net [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Premiums earned, ceded |  |  |  |  |  |  |  |  |  | (125,460) | (52,588) |
Policyholder Benefits and Claims Incurred, Net [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Losses incurred, ceded |  |  |  |  |  |  |  |  |  | (30,201) | (11,424) |
Ceded premiums written, net of profit commission |  |  |  |  |  |  |  |  |  | 125,460 | 52,588 |
Ceded premiums earned, net of profit commission |  |  |  |  |  |  |  |  |  | 125,460 | 52,588 |
Ceded losses incurred |  |  |  |  |  |  |  |  |  | 30,201 | 11,424 |
Ceding commission |  |  |  |  |  |  |  |  |  | 47,629 | 20,582 |
Profit commission |  |  |  |  |  |  |  |  |  | $ 112,685 | 50,322 |
Quota Share Reinsurance Agreement, 2013 |  |  |  |  |  |  |  |  |  |  |  |
Premiums Earned, Net [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Premiums earned, ceded |  |  |  |  |  |  | (11,600) |  |  |  | (35,999) | (88,528)
Policyholder Benefits and Claims Incurred, Net [Abstract] |  |  |  |  |  |  |  |  |  |  |  |
Losses incurred, ceded |  |  |  |  |  |  |  |  |  |  | (6,060) | (15,163)
Ceded premiums written, net of profit commission |  |  |  |  |  |  | 69,400 |  |  |  | (11,355) | 100,031
Ceded premiums earned, net of profit commission |  |  |  |  |  |  | 11,600 |  |  |  | 35,999 | 88,528
Ceded losses incurred |  |  |  |  |  |  |  |  |  |  | 6,060 | 15,163
Ceding commission |  |  |  |  |  |  | $ 11,600 |  |  |  | 10,235 | 37,833
Profit commission | $ 142,500 |  |  |  |  |  |  |  |  |  | $ 62,525 | $ 89,133

X
- Definition Reinsurance, Ceding Commission, Net + References No definition available. + Details
Name: | mtg_ReinsuranceCedingCommissionNet
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 Amount of earned premiums assumed from other entities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 235 -Section S99 -Paragraph 2 -Subparagraph (SX 210.12-17) -URI http://asc.fasb.org/extlink&oid=34713774&loc=d3e574992-122915 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04.1) -URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 605 -Section 50 -Paragraph 1 -Subparagraph (b),(c)(2) -URI http://asc.fasb.org/extlink&oid=6486672&loc=d3e27261-158547 + Details
Name: | us-gaap_AssumedPremiumsEarned
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of earned premiums ceded to other entities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04.1) -URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 605 -Section 50 -Paragraph 1 -Subparagraph (b),(c)(2) -URI http://asc.fasb.org/extlink&oid=6486672&loc=d3e27261-158547 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 605 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6486662&loc=d3e27175-158546 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 235 -Section S99 -Paragraph 2 -Subparagraph (SX 210.12-17) -URI http://asc.fasb.org/extlink&oid=34713774&loc=d3e574992-122915 + Details
Name: | us-gaap_CededPremiumsEarned
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of written premiums ceded to other entities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 605 -Section 50 -Paragraph 1 -Subparagraph (b),(c)(2) -URI http://asc.fasb.org/extlink&oid=6486672&loc=d3e27261-158547 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 17 -Article 12 + Details
Name: | us-gaap_CededPremiumsWritten
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount, before premiums ceded to other entities and premiums assumed by the entity, of premiums earned. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 605 -Section 50 -Paragraph 1 -Subparagraph (b),(c)(1) -URI http://asc.fasb.org/extlink&oid=6486672&loc=d3e27261-158547 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 235 -Section S99 -Paragraph 2 -Subparagraph (SX 210.12-17) -URI http://asc.fasb.org/extlink&oid=34713774&loc=d3e574992-122915 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04.1) -URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913 + Details
Name: | us-gaap_DirectPremiumsEarned
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount, after effect of policies assumed or ceded, of expense related to provision for policy benefits and costs incurred for property and casualty insurance contracts. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04.5) -URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913 + Details
Name: | us-gaap_IncurredClaimsPropertyCasualtyAndLiability
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount, before effect of policies assumed or ceded, of expense related to provision for policy benefits and costs incurred. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04.5) -URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913 + Details
Name: | us-gaap_PolicyholderBenefitsAndClaimsIncurredGross
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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

X
- Definition Amount, after premiums ceded to other entities and premiums assumed by the entity, of property and casualty premiums earned. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04.1) -URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 605 -Section 50 -Paragraph 1 -Subparagraph (b),(c) -URI http://asc.fasb.org/extlink&oid=6486672&loc=d3e27261-158547 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 605 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6486662&loc=d3e27175-158546 + Details
Name: | us-gaap_PremiumsEarnedNetPropertyAndCasualty
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of policy benefits and costs incurred for policies assumed. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 20 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6480758&loc=d3e6811-158387 + Details
Name: | us-gaap_ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountAssumed
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of reduction of provision for policy benefits and costs incurred for policies ceded. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 20 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6480758&loc=d3e6811-158387 + Details
Name: | us-gaap_ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountCeded
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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

X
- Details
Name: | us-gaap_ReinsurancePolicyTypeAxis=mtg_QuotaShareReinsuranceAgreement2015Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ReinsurancePolicyTypeAxis=mtg_QuotaShareReinsuranceAgreement2013Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |