Reserve for Losses and Loss Adjustment Expenses - Narrative (Details) - USD ($)		3 Months Ended			6 Months Ended
	Mar. 31, 2022	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020
Liability for Claims and Claims Adjustment Expense [Abstract]
Allowance for credit losses on reinsurance recoverables	$ 604,000	$ 601,000	$ 604,000	$ 335,000	$ 601,000	$ 335,000	$ 631,000	$ 335,000	$ 335,000
Development on prior year loss reserves
Development on prior year loss reserves		(1,576,000)		(3,450,000)	5,228,000	166,684,000
Funds held		353,685,000			353,685,000		$ 97,360,000
Losses and loss adjustment expenses		121,369,000		110,000,000	256,977,000	383,500,000
Current year		122,945,000		113,450,000	251,749,000	216,816,000
Excess and Surplus Lines
Development on prior year loss reserves
Development on prior year loss reserves		(32,000)		(7,500,000)	(91,000)	161,200,000
Excess and Surplus Lines | Commercial Auto Business
Development on prior year loss reserves
Development on prior year loss reserves						170,000,000
Specialty Admitted Insurance
Development on prior year loss reserves
Development on prior year loss reserves		(1,500,000)		(1,000,000)	(1,500,000)	(2,000,000)
Casualty Reinsurance
Development on prior year loss reserves
Development on prior year loss reserves		$ 0		$ 5,000,000		$ 7,500,000
Casualty Reinsurance | Loss Portfolio Transfer | Fortitude Reinsurance | JRG Reinsurance Company Ltd
Development on prior year loss reserves
Development on prior year loss reserves			6,800,000		$ 6,800,000
Reinsurance, aggregate coverage limit	400,000,000		400,000,000
Ceded premiums payable	335,000,000		335,000,000
Funds held	310,000,000		310,000,000
Payments for reinsurance	$ 25,000,000
Crediting rate on funds withheld	2.00%
Losses and loss adjustment expenses			11,500,000
Current year			$ 4,700,000