Investments - Debt and Short-term Investments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Nov. 10, 2021
Investment Holdings [Line Items]
Other investments	$ 50,501	$ 54,232
Investment in federal home loan bank stock	us-gaap:AssetPledgedAsCollateralMember	us-gaap:AssetPledgedAsCollateralMember
Fair value investments entities that calculate net asset value per share unfunded commitments	$ 20,100
Fixed maturities and short-term investments on deposit with either regulatory authorities or banks	86,200
FHLBC
Investment Holdings [Line Items]
Investments pledged as collateral	64,100
Federal home loan bank borrowings fair value disclosure				$ 50,000
Investment In Low Income Housing Tax Credit Partnership Net Of Amortization
Investment Holdings [Line Items]
Other investments	16,600	$ 20,300
Total tax benefit on investments in housing tax credit partnership	3,600	3,500	$ 2,500
Qualified affordable housing project investments, commitment		1,400
Investment in Private Funds
Investment Holdings [Line Items]
Other investments	28,600	$ 32,100
Fair value investments entities that calculate net asset value per share unfunded commitments	$ 8,800