Investments - Debt and Short-term Investments (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Investment Holdings [Line Items]
Other investments	$ 52,480,000		$ 52,480,000		$ 54,232,000
Investment in federal home loan bank stock	us-gaap:AssetPledgedAsCollateralMember		us-gaap:AssetPledgedAsCollateralMember		us-gaap:AssetPledgedAsCollateralMember
Cash and Short-term Investments
Investment amount	$ 158,721,000		$ 158,721,000		$ 128,382,000
Cash	89,618,000		89,618,000		62,217,000
Other Investments in Unconsolidated Investees
Cash and Short-term Investments
Investment amount	5,700,000		5,700,000
Unfunded commitments	15,000,000.0		15,000,000.0
Maui Jim Inc.
Cash and Short-term Investments
Investment amount	110,600,000		110,600,000
Prime Holdings Insurance Services, Inc. (Prime)
Cash and Short-term Investments
Investment amount	42,400,000		42,400,000
FHLBC
Investment Holdings [Line Items]
Investments pledged as collateral	9,100,000		9,100,000
Federal home loan bank borrowings fair value disclosure	0		0
Investment In Low Income Housing Tax Credit Partnership Net Of Amortization
Investment Holdings [Line Items]
Other investments	17,400,000		17,400,000		20,300,000
Total tax benefit on investments in housing tax credit partnership	900,000	$ 900,000	2,700,000	$ 2,600,000
Qualified affordable housing project investments, commitment	2,100,000		2,100,000
Investment in Private Funds
Investment Holdings [Line Items]
Other investments	31,400,000		31,400,000		$ 32,100,000
Fair value investments entities that calculate net asset value per share unfunded commitments	$ 9,600,000		$ 9,600,000