v2.4.0.8

Investments - Schedule of Investments Reconciliation (Details) (USD $) In Thousands, unless otherwise specified | Mar. 31, 2014 | Dec. 31, 2013
--- | --- | ---
Schedule of Investments [Line Items] |  |
Fixed Maturities, available-for-sale, Amortized cost | $ 3,096,675 | $ 3,127,792
Other Investments, Original or amortized cost | 5,083 | 4,522
Total investments, Original or amortized cost | 3,101,758 | 3,132,314
Available-for-sale securities, Gross unrealized gains | 118,334 | 100,648
Other investments, Gross unrealized gains | 690 | 570
Investments, Gross unrealized gains | 119,024 | 101,218
Available-for-sale securities, Gross unrealized losses | (46,190) | (66,373)
Other investments, Gross unrealized losses | 0 | 0
Investments, Gross unrealized losses | (46,190) | (66,373)
Fair value | 3,168,819 | 3,162,067
Other investments | 5,773 | 5,092
Total investments | 3,174,592 | 3,167,159
U.S. treasury bonds [Member] |  |
Schedule of Investments [Line Items] |  |
Fixed Maturities, available-for-sale, Amortized cost | 16,616 | 16,622
Available-for-sale securities, Gross unrealized gains | 519 | 587
Available-for-sale securities, Gross unrealized losses | 0 | 0
Fair value | 17,135 | 17,209
U.S. agency bonds – mortgage-backed [Member] |  |
Schedule of Investments [Line Items] |  |
Fixed Maturities, available-for-sale, Amortized cost | 1,257,045 | 1,292,032
Available-for-sale securities, Gross unrealized gains | 12,632 | 11,727
Available-for-sale securities, Gross unrealized losses | (34,207) | (41,104)
Fair value | 1,235,470 | 1,262,655
U.S. agency bonds – other [Member] |  |
Schedule of Investments [Line Items] |  |
Fixed Maturities, available-for-sale, Amortized cost | 7,208 | 7,207
Available-for-sale securities, Gross unrealized gains | 988 | 901
Available-for-sale securities, Gross unrealized losses | 0 | 0
Fair value | 8,196 | 8,108
Non-U.S. government bonds [Member] |  |
Schedule of Investments [Line Items] |  |
Fixed Maturities, available-for-sale, Amortized cost | 70,806 | 70,377
Available-for-sale securities, Gross unrealized gains | 3,490 | 3,547
Available-for-sale securities, Gross unrealized losses | (331) | (712)
Fair value | 73,965 | 73,212
Other mortgage-backed securities [Member] |  |
Schedule of Investments [Line Items] |  |
Fixed Maturities, available-for-sale, Amortized cost | 43,952 | 33,676
Available-for-sale securities, Gross unrealized gains | 416 | 0
Available-for-sale securities, Gross unrealized losses | 0 | (232)
Fair value | 44,368 | 33,444
Corporate bonds [Member] |  |
Schedule of Investments [Line Items] |  |
Fixed Maturities, available-for-sale, Amortized cost | 1,638,912 | 1,546,578
Available-for-sale securities, Gross unrealized gains | 98,508 | 82,952
Available-for-sale securities, Gross unrealized losses | (11,652) | (22,830)
Fair value | 1,725,768 | 1,606,700
Municipal bonds – auction rate [Member] |  |
Schedule of Investments [Line Items] |  |
Fixed Maturities, available-for-sale, Amortized cost |  | 99,170
Available-for-sale securities, Gross unrealized gains |  | 0
Available-for-sale securities, Gross unrealized losses |  | 0
Fair value |  | 99,170
Municipal bonds – other [Member] |  |
Schedule of Investments [Line Items] |  |
Fixed Maturities, available-for-sale, Amortized cost | 62,136 | 62,130
Available-for-sale securities, Gross unrealized gains | 1,781 | 934
Available-for-sale securities, Gross unrealized losses | 0 | (1,495)
Fair value | $ 63,917 | $ 61,569

X
- Definition Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax + References No definition available. + Details
Name: | mhld_AvailableforsaleSecuritiesAccumulatedGrossUnrealizedGainbeforeTax
Namespace Prefix: | mhld_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax + References No definition available. + Details
Name: | mhld_AvailableforsaleSecuritiesAccumulatedGrossUnrealizedLossbeforeTax
Namespace Prefix: | mhld_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Investments, Accumulated Gross Unrealized Gain, before Tax + References No definition available. + Details
Name: | mhld_InvestmentsAccumulatedGrossUnrealizedGainbeforeTax
Namespace Prefix: | mhld_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Investments, Accumulated Gross Unrealized Loss, before Tax + References No definition available. + Details
Name: | mhld_InvestmentsAccumulatedGrossUnrealizedLossbeforeTax
Namespace Prefix: | mhld_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Investments, Original or Amortized Cost Basis + References No definition available. + Details
Name: | mhld_InvestmentsOriginalOrAmortizedCostBasis
Namespace Prefix: | mhld_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Other Investments, Accumulated Gross Unrealized Gain, before Tax + References No definition available. + Details
Name: | mhld_OtherInvestmentsAccumulatedGrossUnrealizedGainbeforeTax
Namespace Prefix: | mhld_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Other Investments, Accumulated Gross Unrealized Loss, before Tax + References No definition available. + Details
Name: | mhld_OtherInvestmentsAccumulatedGrossUnrealizedLossbeforeTax
Namespace Prefix: | mhld_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Other Investments, Original or Amortized Cost Basis + References No definition available. + Details
Name: | mhld_OtherInvestmentsOriginalOrAmortizedCostBasis
Namespace Prefix: | mhld_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This item represents the cost of debt securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any. + References No definition available. + Details
Name: | us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of debt 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=28360136&loc=d3e22054-111558 Reference 2: 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=6871852&loc=d3e26610-111562 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27161-111563 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 320 -Section 50 -Paragraph 2 -Subparagraph (b)-(g) -URI http://asc.fasb.org/extlink&oid=6957658&loc=d3e62557-112803 + Details
Name: | us-gaap_AvailableForSaleSecuritiesDebtSecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Sum of the carrying amounts as of the balance sheet date of all investments. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.1(h)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 1 -Subparagraph h -Article 7 + Details
Name: | us-gaap_Investments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Other investments not otherwise specified in the taxonomy. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.12) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 12 -Article 5 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 1 -Subparagraph g -Article 7 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.1(f,g)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 + Details
Name: | us-gaap_OtherInvestments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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