ORGANIZATION, CONSOLIDATION AND BASIS OF PRESENTATION (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2016	Jun. 30, 2016	Mar. 17, 2015
Monarch Delaware Holdings LLC [Member]
Business Organization [Line Item]
Capital contribution for voting interests	$ 14.0	$ 14.0
Ownership interest in Monarch Parent's equity	42.40%	42.40%
Voting interest held in Monarch Parent's equity	50.00%	50.00%
Long-term debt			$ 5.0
Interest rate percentage			6.00%
Monarch Delaware Holdings LLC [Member] \| Crosswinds [Member]
Business Organization [Line Item]
Capital contribution for voting interests	$ 14.0	$ 14.0
Ownership interest in Monarch Parent's equity	42.40%	42.40%
Voting interest held in Monarch Parent's equity	50.00%	50.00%
Monarch Delaware Holdings LLC [Member] \| Transatlantic Reinsurance Company [Member]
Business Organization [Line Item]
Capital contribution for voting interests	$ 5.0	$ 5.0
Ownership interest in Monarch Parent's equity	15.20%	15.20%
Monarch Delaware Holdings LLC [Member] \| Transatlantic Reinsurance Company [Member] \| Senior Debt [Member]
Business Organization [Line Item]
Long-term debt	$ 5.0	$ 5.0
Maturity period of debt		6 years
Interest rate percentage	6.00%	6.00%
Premiums Written, Net [Member] \| Homeowners' Insurance Product Line [Member] \| Customer Concentration Risk [Member] \| ISA [Member]
Concentration Risk [Line Items]
Concentration risk, percentage	24.70%	24.10%

Financial reporting information relating to the business organization.

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