Reserve for Losses and Loss Adjustment Expenses - Retroactive Reinsurance (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Deferred retroactive reinsurance gain at beginning of period			$ 86,720
Adverse prior year development ceded on subject business	$ 6,927	$ 9,239	21,116	$ 7,311
Deferred retroactive reinsurance gain at end of period	107,836		107,836
Excess & Surplus Lines
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Adverse prior year development ceded on subject business	6,927	9,239	21,116	7,311
Commercial Auto LPT, E&S ADC And E&S Top Up ADC \| Excess & Surplus Lines
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Deferred retroactive reinsurance gain at beginning of period	100,909	56,042	86,720	57,970
Adverse prior year development ceded on subject business	7,415	9,168	22,195	9,312
Retroactive reinsurance benefits under the recovery method	(488)	71	(1,079)	(2,001)
Deferred retroactive reinsurance gain at end of period	107,836	65,281	107,836	65,281
Commercial Auto LPT \| Excess & 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	2,336	7,294	2,927	9,222
Adverse prior year development ceded on subject business	(40)	(1,414)	(40)	(1,270)
Retroactive reinsurance benefits under the recovery method	(488)	71	(1,079)	(2,001)
Deferred retroactive reinsurance gain at end of period	1,808	5,951	1,808	5,951
E&S ADC \| Excess & Surplus Lines
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Deferred retroactive reinsurance gain at beginning of period	83,793	48,748	83,793	48,748
Adverse prior year development ceded on subject business	0	10,582	0	10,582
Retroactive reinsurance benefits under the recovery method	0	0	0	0
Deferred retroactive reinsurance gain at end of period	83,793	59,330	83,793	59,330
E&S Top Up ADC \| Excess & Surplus Lines
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Deferred retroactive reinsurance gain at beginning of period	14,780	0	0	0
Adverse prior year development ceded on subject business	7,455	0	22,235	0
Retroactive reinsurance benefits under the recovery method	0	0	0	0
Deferred retroactive reinsurance gain at end of period	$ 22,235	$ 0	$ 22,235	$ 0