Catastrophe Reinsurance - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Liability for Catastrophe Claims [Line Items]
Catastrophic events classification by amount	$ 25,000,000
Ceded earned premiums	42,700,000	$ 36,100,000	$ 31,200,000
Incurred losses and LAE related to prior year (favorable) adverse development	(14,600,000)	106,700,000	36,400,000
Catastrophe
Liability for Catastrophe Claims [Line Items]
Catastrophe Losses and LAE	75,200,000	102,400,000	106,900,000
Incurred losses and LAE related to prior year (favorable) adverse development	(4,100,000)	(5,400,000)	200,000
Catastrophe | Life & Health Insurance
Liability for Catastrophe Claims [Line Items]
Catastrophe Losses and LAE	3,300,000	12,900,000	12,900,000
Incurred losses and LAE related to prior year (favorable) adverse development	1,500,000	(100,000)	500,000
Catastrophe | Specialty Property & Casualty Insurance
Liability for Catastrophe Claims [Line Items]
Catastrophe Losses and LAE	23,600,000	16,000,000.0	12,500,000
Incurred losses and LAE related to prior year (favorable) adverse development	600,000	300,000	200,000
Catastrophe | Preferred Property & Casualty Insurance
Liability for Catastrophe Claims [Line Items]
Catastrophe Losses and LAE	48,300,000	73,500,000	81,500,000
Incurred losses and LAE related to prior year (favorable) adverse development	$ (6,200,000)	$ (5,600,000)	$ (500,000)