Fair Value of Financial Instruments - Schedule of Fair Value Assets and Liabilities Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total available-for-sale fixed-maturity securities	$ 2,705,131	$ 2,702,567
Equity securities	39,531	42,551
Cash and cash equivalents	359,779	392,501
Separate account assets	2,696,891	2,799,992
Separate account liabilities	$ 2,696,891	2,799,992
Fair value assumptions, percentage of securities assessed by third-party pricing service	99.00%
Fair Value, Recurring Measurements [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total available-for-sale fixed-maturity securities	$ 2,705,131	2,702,567
Equity securities	39,531	42,551
Trading securities	12,717	24,355
Cash and cash equivalents	359,779	392,501
Separate account assets	2,696,891	2,799,992
Assets, fair value disclosure	5,857,749	6,047,209
Separate account liabilities	2,696,891	2,799,992
Liabilities, fair value disclosure	2,696,891	2,799,992
Fair Value, Recurring Measurements [Member] \| Level 1 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total available-for-sale fixed-maturity securities	5,518	5,898
Equity securities	35,118	37,912
Cash and cash equivalents	359,779	351,508
Assets, fair value disclosure	400,415	395,318
Fair Value, Recurring Measurements [Member] \| Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total available-for-sale fixed-maturity securities	2,693,710	2,696,642
Equity securities	1,026	1,070
Trading securities	12,717	24,355
Cash and cash equivalents		40,993
Separate account assets	2,696,891	2,799,992
Assets, fair value disclosure	5,446,645	5,648,295
Separate account liabilities	2,696,891	2,799,992
Liabilities, fair value disclosure	2,696,891	2,799,992
Fair Value, Recurring Measurements [Member] \| Level 3 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total available-for-sale fixed-maturity securities	5,903	27
Equity securities	3,387	3,569
Assets, fair value disclosure	10,689	3,596
Fair Value, Recurring Measurements [Member] \| U.S. Government and Agencies [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total available-for-sale fixed-maturity securities	31,911	32,400
Fair Value, Recurring Measurements [Member] \| U.S. Government and Agencies [Member] \| Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total available-for-sale fixed-maturity securities	31,911	32,400
Fair Value, Recurring Measurements [Member] \| Foreign Government [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total available-for-sale fixed-maturity securities	148,991	152,976
Fair Value, Recurring Measurements [Member] \| Foreign Government [Member] \| Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total available-for-sale fixed-maturity securities	148,991	152,976
Fair Value, Recurring Measurements [Member] \| States and Political Subdivisions [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total available-for-sale fixed-maturity securities	141,715	153,527
Fair Value, Recurring Measurements [Member] \| States and Political Subdivisions [Member] \| Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total available-for-sale fixed-maturity securities	141,715	153,527
Fair Value, Recurring Measurements [Member] \| Corporates [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total available-for-sale fixed-maturity securities	1,646,711	1,713,684
Fair Value, Recurring Measurements [Member] \| Corporates [Member] \| Level 1 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total available-for-sale fixed-maturity securities	5,518	5,898
Fair Value, Recurring Measurements [Member] \| Corporates [Member] \| Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total available-for-sale fixed-maturity securities	1,641,193	1,707,786
Fair Value, Recurring Measurements [Member] \| Residential Mortgage-backed Securities [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total available-for-sale fixed-maturity securities	447,124	375,631
Fair Value, Recurring Measurements [Member] \| Residential Mortgage-backed Securities [Member] \| Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total available-for-sale fixed-maturity securities	447,124	375,604
Fair Value, Recurring Measurements [Member] \| Residential Mortgage-backed Securities [Member] \| Level 3 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total available-for-sale fixed-maturity securities		27
Fair Value, Recurring Measurements [Member] \| Commercial Mortgage-backed Securities [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total available-for-sale fixed-maturity securities	142,865	145,525
Fair Value, Recurring Measurements [Member] \| Commercial Mortgage-backed Securities [Member] \| Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total available-for-sale fixed-maturity securities	142,865	145,525
Fair Value, Recurring Measurements [Member] \| Other Asset-backed Securities [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total available-for-sale fixed-maturity securities	145,814	128,824
Fair Value, Recurring Measurements [Member] \| Other Asset-backed Securities [Member] \| Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total available-for-sale fixed-maturity securities	139,911	128,824
Fair Value, Recurring Measurements [Member] \| Other Asset-backed Securities [Member] \| Level 3 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total available-for-sale fixed-maturity securities	5,903
Fair Value, Recurring Measurements [Member] \| Short-Term Investments
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total available-for-sale fixed-maturity securities	43,700	85,243
Fair Value, Recurring Measurements [Member] \| Short-Term Investments \| Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total available-for-sale fixed-maturity securities	42,301	85,243
Fair Value, Recurring Measurements [Member] \| Short-Term Investments \| Level 3 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total available-for-sale fixed-maturity securities	1,399
Fair Value, Recurring Measurements [Member] \| Fixed-Maturity Securities and Short-term Investments [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total available-for-sale fixed-maturity securities	2,748,831	2,787,810
Fair Value, Recurring Measurements [Member] \| Fixed-Maturity Securities and Short-term Investments [Member] \| Level 1 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total available-for-sale fixed-maturity securities	5,518	5,898
Fair Value, Recurring Measurements [Member] \| Fixed-Maturity Securities and Short-term Investments [Member] \| Level 2 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total available-for-sale fixed-maturity securities	2,736,011	2,781,885
Fair Value, Recurring Measurements [Member] \| Fixed-Maturity Securities and Short-term Investments [Member] \| Level 3 [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Total available-for-sale fixed-maturity securities	$ 7,302	$ 27

Fair value assumptions percentage of securities assessed by third party pricing service.

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Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

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Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI), classified as current.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Fair value of financial and nonfinancial obligations.

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Amount of asset at fair value held for benefit of separate account policyholder.

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Amount of liability for variable contract in which all or portion of contract holder's funds is allocated to specific separate account and supported by assets held in separate account.

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Amount of investment in debt security measured at fair value with change in fair value recognized in net income (trading) and investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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