Investments (Commercial Mortgage and Other Loans) (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Commercial Mortgage and Other Loans [Line Items]
Commercial mortgage and agricultural property loans	$ 7,785,059	$ 6,155,050
Commercial mortgage loans, Percentage	100.00%	100.00%
Allowance for Credit Losses	$ (37,715)	$ (37,689)
Commercial mortgage and other loans (net of $36,002 and $36,527 allowance for credit losses at December 31, 2024 and 2023, respectively)	7,759,323	6,122,721
Total net Commercial Mortgage and Other Loans	7,759,323	6,122,721
Other loans	11,979	5,360
Commercial Mortgage and Agricultural Loans
Commercial Mortgage and Other Loans [Line Items]
Commercial mortgage and other loans (net of $36,002 and $36,527 allowance for credit losses at December 31, 2024 and 2023, respectively)	7,747,344	6,117,361
Total net Commercial Mortgage and Other Loans	7,747,344	6,117,361
Other Collateralized Loans
Commercial Mortgage and Other Loans [Line Items]
Other loans	11,979	5,360
Total Net Commercial Mortgage and Other Loans
Commercial Mortgage and Other Loans [Line Items]
Commercial mortgage and other loans (net of $36,002 and $36,527 allowance for credit losses at December 31, 2024 and 2023, respectively)	7,759,323	6,122,721
Total net Commercial Mortgage and Other Loans	7,759,323	6,122,721
Apartments and multi-family
Commercial Mortgage and Other Loans [Line Items]
Commercial mortgage and agricultural property loans	$ 1,949,926	$ 1,578,785
Commercial mortgage loans, Percentage	25.00%	25.70%
Hospitality
Commercial Mortgage and Other Loans [Line Items]
Commercial mortgage and agricultural property loans	$ 97,603	$ 102,952
Commercial mortgage loans, Percentage	1.30%	1.70%
Industrial
Commercial Mortgage and Other Loans [Line Items]
Commercial mortgage and agricultural property loans	$ 2,906,413	$ 2,486,230
Commercial mortgage loans, Percentage	37.30%	40.40%
Office
Commercial Mortgage and Other Loans [Line Items]
Commercial mortgage and agricultural property loans	$ 556,586	$ 604,611
Commercial mortgage loans, Percentage	7.10%	9.80%
Other
Commercial Mortgage and Other Loans [Line Items]
Commercial mortgage and agricultural property loans	$ 750,541	$ 456,720
Commercial mortgage loans, Percentage	9.60%	7.40%
Retail
Commercial Mortgage and Other Loans [Line Items]
Commercial mortgage and agricultural property loans	$ 693,949	$ 363,706
Commercial mortgage loans, Percentage	9.00%	5.90%
Commercial mortgage loans
Commercial Mortgage and Other Loans [Line Items]
Commercial mortgage and agricultural property loans	$ 6,955,018	$ 5,593,004
Commercial mortgage loans, Percentage	89.30%	90.90%
Agricultural property loans
Commercial Mortgage and Other Loans [Line Items]
Commercial mortgage and agricultural property loans	$ 830,041	$ 562,046
Commercial mortgage loans, Percentage	10.70%	9.10%