Investments - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Proceeds from sale of available-for-sale debt securities	$ 32,000,000.0	$ 31,700,000		$ 101,200,000
Gross realized gains from sales of available-for-sale debt securities	5,000	27,000	$ 4,600,000
Gross realized losses from sales of available-for-sale debt securities	155,000	6,000	0
Gross unrealized gains	0	0	1,000,000.0
Gross unrealized losses	638,000	1,000,000.0	0
Amount payable for securities purchased	0	1,000,000.0	700,000
Amount receivable for securities sold	650,000	523,000	$ 809,000
Other than temporary impairments losses, investments	0
Investments	1,800,000
Deposits held in trust accounts	8,000,000.0	8,500,000
Deposits, held in trust for collateral requirements	$ 95,700,000	$ 76,100,000