Segment Reporting - Schedule of Gross Premiums Written by Geographical Location of Subsidiaries (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Revenue and Long-Lived Asset [Line Items]
Gross premiums written	$ 831,041	$ 712,026	$ 1,771,152	$ 1,555,332
Total International
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Revenue and Long-Lived Asset [Line Items]
Gross premiums written	420,073	344,799	862,982	714,757
Lloyd's of London
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Revenue and Long-Lived Asset [Line Items]
Gross premiums written	256,722	204,740	522,039	439,983
Ireland
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Revenue and Long-Lived Asset [Line Items]
Gross premiums written	114,429	98,769	251,075	198,459
U.S.
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Revenue and Long-Lived Asset [Line Items]
Gross premiums written	48,922	41,290	89,868	76,315
Bermuda
Segment Reporting, Entity-Wide Information Not Provided as Part of Reportable Segment, Geographical Area, Revenue and Long-Lived Asset [Line Items]
Gross premiums written	$ 410,968	$ 367,227	$ 908,170	$ 840,575