Investments (Allowance for Credit Losses) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2020	Dec. 31, 2019
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of year	$ 1,768	$ 2,065
Cumulative effect of adoption of ASU 2016-13	2,487
Addition to (release of) allowance for credit losses		(297)
Addition to (release of) allowance for expected losses	259
Total ending balance	4,514	1,768
Commercial Mortgage Loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of year	1,743	2,026
Cumulative effect of adoption of ASU 2016-13	2,495
Addition to (release of) allowance for credit losses		(283)
Addition to (release of) allowance for expected losses	265
Total ending balance	4,503	1,743
Agricultural Property Loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of year	25	39
Cumulative effect of adoption of ASU 2016-13	(8)
Addition to (release of) allowance for credit losses		(14)
Addition to (release of) allowance for expected losses	(6)
Total ending balance	11	25
Other collateralized loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of year	0	0
Cumulative effect of adoption of ASU 2016-13	0
Addition to (release of) allowance for credit losses		0
Addition to (release of) allowance for expected losses	0
Total ending balance	$ 0	$ 0

Cumulative effect of adoption of ASU 2016-13

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- Definition

Amount of increase (decrease) of allowance reserve for credit loss.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.7(d))
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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

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- Definition

Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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- Definition

Amount of expense related to estimated loss from loan and lease transactions.

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-Publisher FASB
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