Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

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The percentage points added to the reference rate to compute the variable rate on the interest rate derivative.

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Amount of right to receive securities collateral under master netting arrangements that have not been offset against derivative liabilities.

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Period the derivative contract is outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Dividends received on equity and other investments during the current period.

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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-Name Accounting Standards Codification
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Condensed Financial Information of Registrant Condensed Financial Information of Registrant (Narratives) (Details)					1 Months Ended	12 Months Ended
	Mar. 29, 2017 USD ($)	Mar. 08, 2017 USD ($)	Feb. 13, 2014 USD ($)	Aug. 09, 2013 USD ($)	Jan. 31, 2017	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Jul. 31, 2018	Jan. 31, 2018	Jul. 07, 2017	Dec. 31, 2016 USD ($)
Condensed Financial Statements, Captions [Line Items]
Capital distribution from subsidiaries						$ 5,200,000	$ 6,000,000.0
Proceeds from dividends received						114,431,433	135,000,000	$ 109,000,000
Repayments of debt		$ 320,000,000
Swap [Member] \| AFL [Member]
Condensed Financial Statements, Captions [Line Items]
Swap agreement collateral				$ 40,000,000
Notional amount												$ 152,000,000
Term of swap agreement				3 years	1 year
Swap [Member] \| AFL [Member] \| LIBOR [Member]
Condensed Financial Statements, Captions [Line Items]
Basis spread on variable rate				1.35%	1.28%			1.35%			1.28%
Swap [Member] \| FFL [Member]
Condensed Financial Statements, Captions [Line Items]
Swap agreement collateral			$ 31,000,000
Notional amount							$ 100,000,000
Term of swap agreement			1 year				1 year
Swap [Member] \| FFL [Member] \| LIBOR [Member]
Condensed Financial Statements, Captions [Line Items]
Basis spread on variable rate			1.28%				1.28%		1.05%	1.20%
Unsecured Notes One [Member] \| Unsecured Debt [Member]
Condensed Financial Statements, Captions [Line Items]
Unsecured debt						$ 375,000,000
Interest rate, stated percentage		4.40%				4.40%
Debt issuance costs		$ 3,400,000
Discount percent		99.847%
Interest rate, effective percentage		4.45%
Unsecured Notes Two [Member] \| Revolving Credit Facility [Member]
Condensed Financial Statements, Captions [Line Items]
Loan maximum borrowing capacity	$ 50,000,000
Unsecured Notes Two [Member] \| Unsecured Debt [Member]
Condensed Financial Statements, Captions [Line Items]
Unsecured debt						$ 0
Minimum [Member] \| Revolving Credit Facility [Member]
Condensed Financial Statements, Captions [Line Items]
Debt to total capital ratio	0.15
Commitment fee on undrawn portion of facility	0.125%
Minimum [Member] \| LIBOR [Member] \| Revolving Credit Facility [Member]
Condensed Financial Statements, Captions [Line Items]
Basis spread on variable rate	1.125%
Debt to total capital ratio	0.15
Minimum [Member] \| Unsecured Notes Two [Member] \| Revolving Credit Facility [Member]
Condensed Financial Statements, Captions [Line Items]
Commitment fee on undrawn portion of facility						0.15%
Minimum [Member] \| Unsecured Notes Two [Member] \| Unsecured Debt [Member] \| LIBOR [Member]
Condensed Financial Statements, Captions [Line Items]
Basis spread on variable rate						0.1125%
Maximum [Member] \| Revolving Credit Facility [Member]
Condensed Financial Statements, Captions [Line Items]
Debt to total capital ratio	0.25
Commitment fee on undrawn portion of facility	0.225%
Maximum [Member] \| LIBOR [Member] \| Revolving Credit Facility [Member]
Condensed Financial Statements, Captions [Line Items]
Basis spread on variable rate	1.625%
Debt to total capital ratio	0.25
Maximum [Member] \| Unsecured Notes Two [Member] \| Revolving Credit Facility [Member]
Condensed Financial Statements, Captions [Line Items]
Debt to total capital ratio						0.172
Maximum [Member] \| Unsecured Notes Two [Member] \| Unsecured Debt [Member] \| LIBOR [Member]
Condensed Financial Statements, Captions [Line Items]
Basis spread on variable rate						0.1625%
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Capital distribution from subsidiaries						$ 30,068,567	$ 0	$ 0
Payments for contributions to subsidiaries						$ 125,000	$ 540,619	$ 140,125,000