Investments (Commercial Mortgage and Other Loans) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Commercial Mortgage and Other Loans [Line Items]
Commercial mortgage and agricultural property loans by property type	$ 1,505,193	$ 1,474,185
Commercial mortgage loans, Percentage	100.00%	100.00%
Allowance for credit losses	$ (6,282)	$ (2,663)
Total commercial mortgage and agricultural loans	3,935	0
Allowance for credit losses, other loans	0	0
Total commercial mortgage and other loans	1,502,846	1,471,522
Commercial Mortgage and Agricultural Loans
Commercial Mortgage and Other Loans [Line Items]
Total commercial mortgage and agricultural loans	1,498,911	1,471,522
Other Collateralized Loans
Commercial Mortgage and Other Loans [Line Items]
Other loans	3,935	0
Apartments and multi-family
Commercial Mortgage and Other Loans [Line Items]
Commercial mortgage and agricultural property loans by property type	$ 288,739	$ 272,150
Commercial mortgage loans, Percentage	19.20%	18.50%
Hospitality
Commercial Mortgage and Other Loans [Line Items]
Commercial mortgage and agricultural property loans by property type	$ 16,721	$ 16,819
Commercial mortgage loans, Percentage	1.10%	1.10%
Industrial
Commercial Mortgage and Other Loans [Line Items]
Commercial mortgage and agricultural property loans by property type	$ 478,089	$ 464,528
Commercial mortgage loans, Percentage	31.80%	31.50%
Office
Commercial Mortgage and Other Loans [Line Items]
Commercial mortgage and agricultural property loans by property type	$ 353,014	$ 372,823
Commercial mortgage loans, Percentage	23.50%	25.30%
Other
Commercial Mortgage and Other Loans [Line Items]
Commercial mortgage and agricultural property loans by property type	$ 155,782	$ 156,768
Commercial mortgage loans, Percentage	10.30%	10.60%
Retail
Commercial Mortgage and Other Loans [Line Items]
Commercial mortgage and agricultural property loans by property type	$ 130,815	$ 131,051
Commercial mortgage loans, Percentage	8.70%	8.90%
Commercial Mortgage Loans
Commercial Mortgage and Other Loans [Line Items]
Commercial mortgage and agricultural property loans by property type	$ 1,423,160	$ 1,414,139
Commercial mortgage loans, Percentage	94.60%	95.90%
Agricultural property loans
Commercial Mortgage and Other Loans [Line Items]
Commercial mortgage and agricultural property loans by property type	$ 82,033	$ 60,046
Commercial mortgage loans, Percentage	5.40%	4.10%

Commercial mortgage loans, Percentage

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Commercial mortgage and agricultural property loans by property type

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Other loans

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The reserve to cover probable credit losses related to specifically identified fixed maturity real estate loans as well as probable credit losses inherent in the remainder of that loan portfolio.

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements and loans held for sale.

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