Investments - Other Investments (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Schedule of Investments [Line Items]
Fair value	$ 5,708	$ 4,877
% of Total fair value	100.00%	100.00%
Other investments	$ 36,054	$ 31,748
Investment in limited partnerships
Schedule of Investments [Line Items]
Fair value	$ 2,908	$ 3,077
% of Total fair value	50.90%	63.10%
Unfunded commitment on investments in limited partnerships	$ 333	$ 340
Other
Schedule of Investments [Line Items]
Fair value	$ 2,800	$ 1,800
% of Total fair value	49.10%	36.90%
Investment in special purpose vehicles focused on lending activities
Schedule of Investments [Line Items]
Other investments	$ 30,346	$ 26,871
Unfunded commitment on investments in limited partnerships	$ 215	$ 767

Other Investments, Percent of Total Fair Value

No definition available.

Name:	mhld_OtherInvestmentsPercentOfTotalFairValue
Namespace Prefix:	mhld_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The amount of unfunded commitments for which the entity is obligated, to those certain investments for which net asset value per share is calculated (including by unit, membership interest, or other equity (ownership interest) unit measure) (alternative investments).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 6A
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=SL6742756-110258

+ Details

Name:	us-gaap_FairValueInvestmentsEntitiesThatCalculateNetAssetValuePerShareUnfundedCommittments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Value of the other investment not readily marketable determined by management based upon fair value methods, including pricing of similar securities and valuation techniques, that was used to record the investment for financial reporting purposes.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 940
-SubTopic 820
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=35710923&loc=d3e45360-110995

+ Details

Name:	us-gaap_OtherInvestmentNotReadilyMarketableFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of investments classified as other.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-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=120400017&loc=d3e572229-122910

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-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=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_OtherInvestments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- 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_ScheduleOfInvestmentsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_InvestmentTypeAxis=srt_PartnershipInterestMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InvestmentTypeAxis=us-gaap_OtherInvestmentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InvestmentTypeAxis=mhld_SpecialPurposeVehiclesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: