Investments - Narrative (Details)		12 Months Ended
	Dec. 31, 2020 USD ($) loan	Dec. 31, 2021 USD ($) mortgage_loan	Dec. 31, 2020 USD ($) loan	Dec. 31, 2019 USD ($) nursing_home	Dec. 30, 2020 USD ($)	Jan. 01, 2020 USD ($)	Jan. 31, 2019 USD ($)
Schedule of Investments [Line Items]
Loans originated during the year		$ 183,600,000	$ 80,200,000
Number of mortgage loan | mortgage_loan		3
Net investments in mortgage loans, after allowances for possible losses	$ 332,521,000	$ 487,304,000	332,521,000
Mortgage loans-allowance for possible losses	2,486,000	2,987,000	2,486,000
Increase (decrease) to retained earnings	2,102,577,000	2,281,986,000	2,102,577,000
Real estate investments	104,113,000	137,670,000	104,113,000
Gain (loss) on sale of property		(1,400,000)	2,700,000
Real estate gain (loss)		(1,421,000)	2,661,000	$ 6,911,000
Debt securities, available-for-sale	$ 10,770,923,000	9,068,946,000	10,770,923,000
Realized gains on investments		14,950,000	21,071,000	6,241,000
Securities, other-than-temporarily impaired				7,800,000
Transfer, fair value		0	7,300,000,000	0
Transfer, amortized cost		0	6,700,000,000	0
Unrealized gain (loss) transferred		0	$ 600,000,000	0
Loans In Forbearance
Schedule of Investments [Line Items]
Number of loans | loan	1		8
Loans receivable		4,700,000			$ 29,200,000
Cumulative Effect, Period of Adoption, Adjustment
Schedule of Investments [Line Items]
Mortgage loans-allowance for possible losses						$ 1,200,000
Increase (decrease) to retained earnings						3,000,000
Cumulative Effect, Period of Adoption, Adjustment | Accounting Standards Update 2016-13
Schedule of Investments [Line Items]
Increase (decrease) to retained earnings						$ 400,000
Real Estate
Schedule of Investments [Line Items]
Real estate investments	$ 33,800,000	28,600,000	$ 33,800,000
Operating income recognized on real estate investment properties		2,900,000	2,900,000	2,900,000
Mortgage loan investment
Schedule of Investments [Line Items]
Loan investments made by reinsurer		8,500,000
External Credit Rating, Non Investment Grade | Debt Securities
Schedule of Investments [Line Items]
Debt securities, available-for-sale	$ 303,500,000	$ 153,000,000	$ 303,500,000
Debt securities below investment grade, percentage of total invested assets	2.70%	1.40%	2.70%
Non- Income Producing
Schedule of Investments [Line Items]
Real estate investment	$ 400,000	$ 100,000	$ 400,000	400,000
Prior Home Office
Schedule of Investments [Line Items]
Gain (loss) on sale of property				3,200,000
Nursing Home Facilities
Schedule of Investments [Line Items]
Gain (loss) on sale of property				$ 3,700,000
Number of nursing home | nursing_home				2
Ozark National Life Insurance Company:
Schedule of Investments [Line Items]
Debt securities, available-for-sale	$ 811,600,000	$ 823,000,000	$ 811,600,000
Ozark National Life Insurance Company: | Real Estate
Schedule of Investments [Line Items]
Real estate investments							$ 4,300,000