Investments - Net Investment Income (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Net Investment Income [Line Items]
Gross investment income	$ 154,956	$ 160,633	$ 179,932
Investment expenses	(7,047)	(6,596)	(8,136)
Net investment income	147,909	154,037	171,796
Fixed-maturities available for sale
Net Investment Income [Line Items]
Gross investment income	145,613	148,127	155,104
Equity securities
Net Investment Income [Line Items]
Gross investment income	8,158	6,378	7,028
Short-term investments
Net Investment Income [Line Items]
Gross investment income	817	5,774	17,255
Other
Net Investment Income [Line Items]
Gross investment income	$ 368	$ 354	$ 545

Amount, before investment expense, of income earned from investments in securities and real estate. Includes, but is not limited to, real estate investment, policy loans, dividends, and interest. Excludes realized gain (loss) on investments.

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-SubTopic 220
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Amount of expenses related to the generation of investment income.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Amount after accretion (amortization) of discount (premium), and investment expense, of interest income and dividend income on nonoperating securities.

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