Fair Values of Financial Instruments - Schedule of Carrying Amounts and Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
ASSETS
Debt securities, available-for-sale	$ 7,611,633	$ 9,068,946
Debt securities, trading	1,065,993	1,077,438
Other loans	19,334	8,469
Derivatives, index options	23,669	101,622
Equity securities:	22,076	28,217
Carrying Values
ASSETS
Debt securities, available-for-sale	7,611,633	9,068,946
Debt securities, trading	1,065,993	1,077,438
Cash and cash equivalents	295,270	714,624
Mortgage loans	505,730	487,304
Real estate	27,712	28,606
Policy loans	70,495	71,286
Other loans	31,586	24,266
Derivatives, index options	23,669	101,622
Equity securities:	22,076	28,217
Short-term investments	3,937
Life interest in Libbie Shearn Moody Trust	7,100	8,254
Other investments	4,513	4,537
LIABILITIES
Deferred annuity contracts	6,054,030	6,463,314
Immediate annuity and supplemental contracts	397,318	422,209
Fair Values
ASSETS
Debt securities, available-for-sale	7,611,633	9,068,946
Debt securities, trading	1,065,993	1,077,438
Cash and cash equivalents	295,270	714,624
Mortgage loans	457,873	513,246
Real estate	47,867	47,027
Policy loans	87,478	110,492
Other loans	31,915	25,085
Derivatives, index options	23,669	101,622
Equity securities:	22,076	28,217
Short-term investments	3,937
Life interest in Libbie Shearn Moody Trust	12,775	12,775
Other investments	26,230	24,876
LIABILITIES
Deferred annuity contracts	4,405,510	4,703,331
Immediate annuity and supplemental contracts	373,346	457,787
Level 1
ASSETS
Debt securities, available-for-sale	0	0
Debt securities, trading	0	0
Cash and cash equivalents	295,270	702,632
Mortgage loans	0	0
Real estate	0	0
Policy loans	0	0
Other loans	0	0
Derivatives, index options	0	0
Equity securities:	18,407	23,795
Short-term investments	0
Life interest in Libbie Shearn Moody Trust	0	0
Other investments	0	0
LIABILITIES
Deferred annuity contracts	0	0
Immediate annuity and supplemental contracts	0	0
Level 2
ASSETS
Debt securities, available-for-sale	7,148,837	8,741,984
Debt securities, trading	942,756	1,002,616
Cash and cash equivalents	0	11,992
Mortgage loans	0	0
Real estate	0	0
Policy loans	0	0
Other loans	0	0
Derivatives, index options	0	0
Equity securities:	3,669	4,422
Short-term investments	3,937
Life interest in Libbie Shearn Moody Trust	0	0
Other investments	0	0
LIABILITIES
Deferred annuity contracts	0	0
Immediate annuity and supplemental contracts	0	0
Level 3
ASSETS
Debt securities, available-for-sale	462,796	326,962
Debt securities, trading	123,237	74,822
Cash and cash equivalents	0	0
Mortgage loans	457,873	513,246
Real estate	47,867	47,027
Policy loans	87,478	110,492
Other loans	31,915	25,085
Derivatives, index options	23,669	101,622
Equity securities:	0	0
Short-term investments	0
Life interest in Libbie Shearn Moody Trust	12,775	12,775
Other investments	26,230	24,876
LIABILITIES
Deferred annuity contracts	4,405,510	4,703,331
Immediate annuity and supplemental contracts	$ 373,346	$ 457,787

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