Investments - Schedule of Commercial Mortgage Loan Participations Recorded Investment (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying value, net of valuation allowance	$ 228,802		$ 181,305
Carrying value	231,790		183,094
Less allowance for credit losses	$ (2,988)	$ (2,928)	$ (1,789)	$ (2,160)	$ (1,109)	$ (827)
Carrying value, net of valuation allowance, percent	100.00%		100.00%
Less than 70%
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying value	$ 215,211		$ 144,395
Carrying value, net of valuation allowance, percent	93.00%		79.00%
70% to 80%
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying value	$ 0		$ 23,358
Carrying value, net of valuation allowance, percent	0.00%		13.00%
81% to 90%
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying value	$ 9,544		$ 8,307
Carrying value, net of valuation allowance, percent	4.00%		4.00%
Greater than 90%
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying value	$ 7,035		$ 7,034
Carrying value, net of valuation allowance, percent	3.00%		4.00%
Less Than 1.00x
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying value, net of valuation allowance	$ 42,413		$ 39,562
Less Than 1.00x | Less than 70%
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying value, net of valuation allowance	26,987		24,221
Less Than 1.00x | 70% to 80%
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying value, net of valuation allowance	0		0
Less Than 1.00x | 81% to 90%
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying value, net of valuation allowance	8,391		8,307
Less Than 1.00x | Greater than 90%
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying value, net of valuation allowance	7,035		7,034
1.00x-1.20x
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying value, net of valuation allowance	151,455		130,276
1.00x-1.20x | Less than 70%
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying value, net of valuation allowance	151,455		108,156
1.00x-1.20x | 70% to 80%
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying value, net of valuation allowance	0		22,120
1.00x-1.20x | 81% to 90%
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying value, net of valuation allowance	0		0
1.00x-1.20x | Greater than 90%
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying value, net of valuation allowance	0		0
Greater Than 1.20x
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying value, net of valuation allowance	37,922		13,256
Greater Than 1.20x | Less than 70%
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying value, net of valuation allowance	36,769		12,018
Greater Than 1.20x | 70% to 80%
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying value, net of valuation allowance	0		1,238
Greater Than 1.20x | 81% to 90%
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying value, net of valuation allowance	1,153		0
Greater Than 1.20x | Greater than 90%
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying value, net of valuation allowance	$ 0		$ 0