Reserve for Losses and Loss Adjustment Expenses - Retroactive Reinsurance (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Deferred retroactive reinsurance gain at beginning of period	$ 57,970
Adverse prior year development ceded on subject business	(131)	$ (398)
Deferred retroactive reinsurance gain at end of period	56,042
Excess and Surplus Lines
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Adverse prior year development ceded on subject business	(10)	40
Commercial Auto LPT And E&S ADC | Excess and Surplus Lines
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Deferred retroactive reinsurance gain at beginning of period	57,970	20,733
Adverse prior year development ceded on subject business	144	477
Retroactive reinsurance benefits under the recovery method	(2,072)	(4,479)
Deferred retroactive reinsurance gain at end of period	56,042	16,731
Commercial Auto LPT | Excess and Surplus Lines | Commercial Auto LPT
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Deferred retroactive reinsurance gain at beginning of period	9,222	20,733
Adverse prior year development ceded on subject business	144	477
Retroactive reinsurance benefits under the recovery method	(2,072)	(4,479)
Deferred retroactive reinsurance gain at end of period	7,294	16,731
E&S ADC | Excess and Surplus Lines
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Deferred retroactive reinsurance gain at beginning of period	48,748	0
Adverse prior year development ceded on subject business	0	0
Retroactive reinsurance benefits under the recovery method	0	0
Deferred retroactive reinsurance gain at end of period	$ 48,748	$ 0