v2.4.0.8

Investments - Realized and Unrealized Gains on Investment (Details) (USD $) In Thousands, unless otherwise specified | 3 Months Ended | 6 Months Ended | 12 Months Ended
--- | --- | --- | ---
Jun. 30, 2013 | Jun. 30, 2012 | Jun. 30, 2013 | Jun. 30, 2012 | Dec. 31, 2012
Gain (Loss) on Investments [Line Items] |  |  |  |  |
Gross gains | $ 0 | $ 9 | $ 3,283 | $ 20 |
Gross losses | (53) | (2,948) | (53) | (1,594) |
Realized gains (losses), Net | (53) | (2,939) | 3,230 | (1,574) |
Proceeds from sales of fixed maturities classified as available-for-sale |  |  | 202,486 | 104,125 |
Net unrealized gains | 49,348 |  | 49,348 |  | 143,797
Deferred income tax expense | (101) |  | (101) |  | (132)
Net unrealized gains, net of deferred income tax | 49,247 |  | 49,247 |  | 143,665
Change in net unrealized gains, net of deferred income tax |  |  | (94,418) |  | 79,928
Available-for-sale securities [Member] |  |  |  |  |
Gain (Loss) on Investments [Line Items] |  |  |  |  |
Gross gains |  |  | 3,112 |  |
Gross losses |  |  | 0 |  |
Realized gains (losses), Net |  |  | 3,112 |  |
Net unrealized gains | 48,997 |  | 48,997 |  | 143,495
Trading Securities and Short Sales [Member] |  |  |  |  |
Gain (Loss) on Investments [Line Items] |  |  |  |  |
Gross gains |  | 0 |  | 0 |
Gross losses |  | (2,948) |  | (1,593) |
Realized gains (losses), Net |  | (2,948) |  | (1,593) |
Other investments [Member] |  |  |  |  |
Gain (Loss) on Investments [Line Items] |  |  |  |  |
Gross gains | 0 | 9 | 171 | 20 |
Gross losses | (53) | 0 | (53) | (1) |
Realized gains (losses), Net | (53) | 9 | 118 | 19 |
Net unrealized gains | $ 351 |  | $ 351 |  | $ 302

X
- Definition Gross Realized Gains + References No definition available. + Details
Name: | mhld_GrossRealizedGains
Namespace Prefix: | mhld_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Gross Realized Losses + References No definition available. + Details
Name: | mhld_GrossRealizedLosses
Namespace Prefix: | mhld_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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

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

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 Amount of deferred tax liability attributable to taxable temporary differences from capitalized costs. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32621-109319 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 25 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=29652012&loc=d3e28680-109314 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32632-109319 + Details
Name: | us-gaap_DeferredTaxLiabilitiesDeferredExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The cash inflow associated with the sale of debt securities classified as available-for-sale securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Investing Activities -URI http://asc.fasb.org/extlink&oid=6516133 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26853-111562 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 12 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3179-108585 + Details
Name: | us-gaap_ProceedsFromSaleOfAvailableForSaleSecuritiesDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition This item represents the total realized gain (loss) included in earnings for the period as a result of selling marketable securities categorized as trading, available-for-sale, or held-to-maturity and any gains or losses realized during the period from the sale of investments accounted for under the cost method of accounting and/or investments that are separately or otherwise not categorized as trading, available-for-sale, or held-to-maturity. Additionally, this item would include any losses recognized for other than temporary impairments (OTTI) of the subject investments in debt and equity securities. + References No definition available. + Details
Name: | us-gaap_RealizedGainLossOnMarketableSecuritiesCostMethodInvestmentsAndOtherInvestments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_ScheduleOfGainLossOnInvestmentsIncludingMarketableSecuritiesAndInvestmentsHeldAtCostIncomeStatementReportedAmountsSummaryLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration