Segment Information - Net Premiums (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Segment Reporting, Revenue Reconciling Item [Line Items]
Net premiums written	$ (10,323)	$ (2,696)
% of total net premiums written	100.00%	100.00%
Net premiums earned	$ 1,122	$ 11,764
% of total net premiums earned	100.00%	100.00%
Diversified Reinsurance | Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Net premiums written	$ 4,583	$ (234)
% of total net premiums written	(44.40%)	8.70%
Net premiums earned	$ 5,955	$ 6,240
% of total net premiums earned	530.70%	53.10%
Diversified Reinsurance | International | Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Net premiums written	$ 4,583	$ (244)
% of total net premiums written	(44.40%)	9.10%
Net premiums earned	$ 5,955	$ 6,230
% of total net premiums earned	530.70%	53.00%
Diversified Reinsurance | Other | Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Net premiums written	$ 0	$ 10
% of total net premiums written	0.00%	(0.40%)
Net premiums earned	$ 0	$ 10
% of total net premiums earned	0.00%	0.10%
AmTrust Reinsurance | Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Net premiums written	$ (14,906)	$ (2,462)
% of total net premiums written	144.40%	91.30%
Net premiums earned	$ (4,833)	$ 5,524
% of total net premiums earned	(430.70%)	46.90%
AmTrust Reinsurance | Small Commercial Business | Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Net premiums written	$ (11,722)	$ (2,478)
% of total net premiums written	113.50%	91.90%
Net premiums earned	$ (11,710)	$ (2,351)
% of total net premiums earned	(1043.60%)	(20.00%)
AmTrust Reinsurance | Specialty Program | Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Net premiums written	$ 837	$ (25)
% of total net premiums written	(8.10%)	0.90%
Net premiums earned	$ 838	$ (18)
% of total net premiums earned	74.70%	(0.20%)
AmTrust Reinsurance | Specialty Risk and Extended Warranty | Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Net premiums written	$ (4,021)	$ 41
% of total net premiums written	39.00%	(1.50%)
Net premiums earned	$ 6,039	$ 7,893
% of total net premiums earned	538.20%	67.10%