Reinsurance and Indemnification - New Jersey Property-Liability Insurance Guaranty Association (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
New Jersey Unsatisfied Claim and Judgment Fund
Reinsurance Retention Policy [Line Items]
Minimum medical benefits portion of personal injury protection coverage for reimbursement to insurers for policies issued or renewed prior to January 1, 1991	$ 75
Minimum medical benefits portion of personal injury protection coverage for reimbursement to insurers for policies issued or renewed from January 1, 1991 to December 31, 2004	75
Maximum reimbursement to insurers for medical benefits paid under personal injury protection coverage.	250
Reinsurance, administration assessments paid	7,000
Reinsurance and indemnification recoverables, net	$ 326,000	$ 330,000
Insurance fund balance		71,000
PLGIA
Reinsurance Retention Policy [Line Items]
Insurance fund balance		$ 271,000