Investments (Allowance for Credit Losses) (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of year	$ 5,951	$ 4,552
Addition to (release of) allowance for expected losses	495	(238)
Total ending balance	6,446	4,314
Commercial mortgage loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of year	5,847	4,546
Addition to (release of) allowance for expected losses	477	(237)
Total ending balance	6,324	4,309
Agricultural Property Loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance, beginning of year	104	6
Addition to (release of) allowance for expected losses	18	(1)
Total ending balance	$ 122	$ 5

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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (c)(1)
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Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 210
-Section S99
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-Subparagraph (SX 210.9-03(7)(2))
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher SEC
-Name Regulation S-K (SK)
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Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher SEC
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Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher SEC
-Name Regulation S-K (SK)
-Number 229
-Section 1405
-Paragraph (a)
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Name:	us-gaap_FinancingReceivableAllowanceForCreditLosses
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant