Investment Operations Allowance on Mortgage Loans (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Allowance on mortgage loans	$ 3,107	$ 497
Provision for Loan, Lease, and Other Losses	0	2,778
Charge offs	2,778	168
Allowance on mortgage loans	$ 329	$ 3,107

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
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Name:	us-gaap_FinancingReceivableAllowanceForCreditLosses
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant