v3.21.2

Investments - Realized Gains (Losses) on Investment (Details) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended | 12 Months Ended
--- | --- | --- | ---
Jun. 30, 2021 | Jun. 30, 2020 | Jun. 30, 2021 | Jun. 30, 2020 | Dec. 31, 2020
Gain (Loss) on Securities [Line Items] |  |  |  |  |
Equity securities, gross gains | $ 0 |  | $ 4,957 |  |
Equity securities, gross losses | (611) |  | (611) |  |
Equity securities, net | (611) | $ 0 | 4,346 | $ 0 |
Net realized gains (losses) on investment, gross gains | 1,555 | 9,059 | 9,830 | 20,098 |
Net realized gains (losses) on investment, gross losses | (706) | (184) | (880) | (185) |
Net realized gains (losses) on investment | 849 | 8,875 | 8,950 | 19,913 |
Less: Net gains recognized for equity securities divested during the period | 0 | 0 | (441) | 0 |
Unrealized (losses) gains recognized for equity securities still held at reporting date | (611) | 0 | 3,905 | 0 |
Proceeds from sales of fixed maturities classified as available-for-sale | 52,538 | 181,030 | 206,354 | 405,501 |
Equity method investments | (3,419) |  | (3,419) |  | $ 0
Total net unrealized gains | 23,719 |  | 23,719 |  | 49,488
Deferred income tax | (87) |  | (87) |  | (131)
Net unrealized gains, net of deferred income tax | 23,632 |  | 23,632 |  | 49,357
Change in net unrealized (losses) gains on investment |  |  | (25,725) |  | 27,361
Fixed maturities |  |  |  |  |
Gain (Loss) on Securities [Line Items] |  |  |  |  |
Fixed maturities, gross gains | 1,204 | 9,059 | 4,247 | 19,991 |
Fixed maturities, gross losses | (95) | 0 | (244) | (1) |
Fixed maturities, net | 1,109 | 9,059 | 4,003 | 19,990 |
Other Debt Obligations |  |  |  |  |
Gain (Loss) on Securities [Line Items] |  |  |  |  |
Other investments, gross gains | 351 | 0 | 626 | 107 |
Other investments, gross losses | 0 | (184) | (25) | (184) |
Other investments, net | 351 | $ (184) | 601 | $ (77) |
Available-for-sale securities | Fixed maturities |  |  |  |  |
Gain (Loss) on Securities [Line Items] |  |  |  |  |
Fixed maturities | $ 27,138 |  | $ 27,138 |  | $ 49,488

X
- Definition Equity Method Investment, Unrealized Gain (Loss) + References No definition available. + Details
Name: | mhld_EquityMethodInvestmentUnrealizedGainLoss
Namespace Prefix: | mhld_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Equity Securities, FV-NI, Realized And Unrealized Gain + References No definition available. + Details
Name: | mhld_EquitySecuritiesFVNIRealizedAndUnrealizedGain
Namespace Prefix: | mhld_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Equity Securities, FV-NI, Realized And Unrealized Loss + References No definition available. + Details
Name: | mhld_EquitySecuritiesFVNIRealizedAndUnrealizedLoss
Namespace Prefix: | mhld_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Investments, Gross Unrealized Gain (Loss), Net of Deferred Income Tax Expense + References No definition available. + Details
Name: | mhld_InvestmentsGrossUnrealizedGainLossNetOfDeferredIncomeTaxExpense
Namespace Prefix: | mhld_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Investments, Net Unrealized Gain (Loss) + References No definition available. + Details
Name: | mhld_InvestmentsNetUnrealizedGainLoss
Namespace Prefix: | mhld_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Investments, Unrealized Gain (Loss), Gross Of Deferred Income Tax Expense + References No definition available. + Details
Name: | mhld_InvestmentsUnrealizedGainLossGrossOfDeferredIncomeTaxExpense
Namespace Prefix: | mhld_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Marketable Securities, Realized Gain + References No definition available. + Details
Name: | mhld_MarketableSecuritiesRealizedGain
Namespace Prefix: | mhld_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Marketable Securities, Realized Loss + References No definition available. + Details
Name: | mhld_MarketableSecuritiesRealizedLoss
Namespace Prefix: | mhld_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Other Comprehensive Income (Loss), Investments Adjustment, Net of Tax, Portion Attributable To Parent + References No definition available. + Details
Name: | mhld_OtherComprehensiveIncomeLossInvestmentsAdjustmentNetOfTaxPortionAttributableToParent
Namespace Prefix: | mhld_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Realized And Unrealized Gain On Investments + References No definition available. + Details
Name: | mhld_RealizedAndUnrealizedGainOnInvestments
Namespace Prefix: | mhld_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Realized And Unrealized Loss On Investments + References No definition available. + Details
Name: | mhld_RealizedAndUnrealizedLossOnInvestments
Namespace Prefix: | mhld_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of realized gain on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27357-111563 + Details
Name: | us-gaap_DebtSecuritiesAvailableForSaleRealizedGain
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of realized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27357-111563 + Details
Name: | us-gaap_DebtSecuritiesAvailableForSaleRealizedGainLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of realized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27357-111563 + Details
Name: | us-gaap_DebtSecuritiesAvailableForSaleRealizedLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of deferred tax liability attributable to taxable temporary differences from capitalized costs. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32621-109319 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32632-109319 + Details
Name: | us-gaap_DeferredTaxLiabilitiesDeferredExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of unrealized and realized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 321 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=123583765&loc=SL75117546-209714 + Details
Name: | us-gaap_EquitySecuritiesFvNiGainLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of realized gain (loss) from sale of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 321 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=123583765&loc=SL75117546-209714 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 220 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04(3)(d)) -URI http://asc.fasb.org/extlink&oid=120400993&loc=SL114874131-224263 + Details
Name: | us-gaap_EquitySecuritiesFvNiRealizedGainLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of unrealized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 220 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04(3)(d)) -URI http://asc.fasb.org/extlink&oid=120400993&loc=SL114874131-224263 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 321 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=123583765&loc=SL75117546-209714 + Details
Name: | us-gaap_EquitySecuritiesFvNiUnrealizedGainLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of realized and unrealized gain (loss) on investment. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 10 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27405-111563 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.7(c),9(a)) -URI http://asc.fasb.org/extlink&oid=123367319&loc=SL114868664-224227 Reference 3: http://www.xbrl.org/2003/role/recommendedDisclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3602-108585 + Details
Name: | us-gaap_GainLossOnInvestments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of realized gain (loss) on investment in marketable security, including other-than-temporary impairment (OTTI). + References No definition available. + Details
Name: | us-gaap_MarketableSecuritiesRealizedGainLoss
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of cash inflow from sale of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=124260329&loc=d3e26853-111562 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3151-108585 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 12 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3179-108585 + Details
Name: | us-gaap_ProceedsFromSaleOfAvailableForSaleSecuritiesDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
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_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_FixedMaturitiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_OtherDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_IncomeStatementLocationAxis=us-gaap_AvailableforsaleSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |