Investments - Schedule of Loans by Ratio (Details) $ in Millions	Mar. 31, 2023 USD ($) loan security	Dec. 31, 2022 USD ($) loan security
Accounts, Notes, Loans and Financing Receivable [Line Items]
Cost	$ 159.9	$ 159.9
Loan Count | loan	28	28
Equal to or less than 50.0%
Accounts, Notes, Loans and Financing Receivable [Line Items]
Cost	$ 36.7	$ 36.7
Loan Count | security	6	6
Greater than 50.0% to 55.0%
Accounts, Notes, Loans and Financing Receivable [Line Items]
Cost	$ 9.1	$ 9.1
Loan Count | security	2	2
Greater than 55.0% to 60.0%
Accounts, Notes, Loans and Financing Receivable [Line Items]
Cost	$ 42.6	$ 42.6
Loan Count | security	8	8
Greater than 60.0% to 70.0%
Accounts, Notes, Loans and Financing Receivable [Line Items]
Cost	$ 61.5	$ 71.5
Loan Count | security	10	12
Greater than 70.0%
Accounts, Notes, Loans and Financing Receivable [Line Items]
Cost	$ 10.0
Loan Count | security	2
1.00 to 1.50
Accounts, Notes, Loans and Financing Receivable [Line Items]
Cost	$ 30.4	$ 10.4
Loan Count | security	6	2
Greater than 1.5 to 2.0
Accounts, Notes, Loans and Financing Receivable [Line Items]
Cost	$ 71.7	$ 60.4
Loan Count | security	12	10
Greater than 2.0 to 3.0
Accounts, Notes, Loans and Financing Receivable [Line Items]
Cost	$ 32.0	$ 52.0
Loan Count | security	6	10
Greater than 3.0 to 4.0
Accounts, Notes, Loans and Financing Receivable [Line Items]
Cost	$ 25.8	$ 25.8
Loan Count | security	4	4
Greater than 4.0
Accounts, Notes, Loans and Financing Receivable [Line Items]
Cost	$ 0.0	$ 11.3
Loan Count | security	0	2