Investment Securities - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Marketable Securities [Line Items]
Security Owned and Pledged as Collateral Carrying Value	$ 564,400,000	$ 324,400,000
OTTI	0	0
Realized Investment Gains (Losses)	2,200,000	1,500,000	$ 24,000
Realized Investment Gains Losses, Net of Tax	1,800,000	1,200,000	19,000
Equity securities	14,097,000	1,090,000
Gain (loss) on equity securities	$ 2,000,000.0	90,000	$ 0
Preferred Stock [Member]
Marketable Securities [Line Items]
Equity securities		$ 1,100,000