Significant Accounting Policies - Additional Information (Detail) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2018 USD ($)	Dec. 31, 2019 USD ($) numberOfSegments	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 numberOfSegments
Significant of Account Policies [Line Items]
Number of reportable segments | numberOfSegments		4
Concentration risk percentage		100.00%
Number of operating segments sold | numberOfSegments					1
Percentage of investment securities not classified as corporate securities, state and municipal securities, redeemable preferred stocks and U.S. government securities (less than)		2.00%
Fair value determined by third party		96.00%
Advanced agent commissions receivable	$ 396,000	$ 424,000	$ 396,000
Advertising costs charged to earnings and included in other operating		9,500	9,000	$ 9,300
Capitalized advertising costs	1,300,000	1,300,000	1,300,000
Carrying value of investment in low-income housing interests	226,000	206,000	226,000
Obligations under future commitments for low-income housing interests		52,000
Original cost of property and equipment	256,000	298,000	256,000
Accumulated depreciation	121,000	137,000	121,000
Depreciation expense		$ 16,000	13,000	11,000
Traditional life and health, interest rate, low end		2.50%
Traditional life and health, interest rate, high end		7.00%
Traditional life and health, weighted average interest rate		5.70%
Tax benefit as the result of a lower corporate tax rate				874,000
Tax reform adjustment	$ 798	$ 0	(798)	(877,400)
Insurance policy charges		$ 15,600	$ 16,400	$ 17,000
Total investments | Unconsolidated variable interest entity risk
Significant of Account Policies [Line Items]
Concentration risk percentage		1.00%
Equity Option | Torchmark Corporation 2018 Incentive Plan
Significant of Account Policies [Line Items]
Term over which monthly data points are used to derive volatility		3 years
Equity Option | Employee | Three Year Vesting Period | Torchmark Corporation 2018 Incentive Plan
Significant of Account Policies [Line Items]
Option grants contractual term		7 years
Vesting period		3 years
Equity Option | Employee | Five Year Vesting Period | Torchmark Corporation 2018 Incentive Plan
Significant of Account Policies [Line Items]
Option grants contractual term		10 years
Vesting period		5 years
Equity Option | Director | Torchmark Corporation 2018 Incentive Plan
Significant of Account Policies [Line Items]
Vesting period		6 months
Life insurance
Significant of Account Policies [Line Items]
Proportion of future policy reserves which are not universal life type		89.00%
Equipment | Minimum
Significant of Account Policies [Line Items]
Property and equipment, estimated useful life		3 years
Equipment | Maximum
Significant of Account Policies [Line Items]
Property and equipment, estimated useful life		10 years
Building and Improvements | Minimum
Significant of Account Policies [Line Items]
Property and equipment, estimated useful life		15 years
Building and Improvements | Maximum
Significant of Account Policies [Line Items]
Property and equipment, estimated useful life		40 years