Retirement and Compensation Plans FBL's share of prepaid or accrued pension costs (Details) - USD ($) $ in Thousands		Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Multiemployer unrecognized liability for underfunded status		$ 18,300	$ 3,900
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Assets for Plan Benefits, Defined Benefit Plan		38,365	36,105
Liability, Defined Benefit Plan		0	(12)
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position		38,365	36,093
Other Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Assets for Plan Benefits, Defined Benefit Plan		749	726
Liability, Defined Benefit Plan		(21,922)	(19,480)
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position		(21,173)	(18,754)
Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), Gain (Loss), before Tax	[1]	12,990	11,126
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax	[1]	$ 12,990	$ 11,126

[1] For our Multiemployer Plan, the underfunded portion of the pension benefit obligation is not required to be recognized as a liability in our consolidated balance sheets. The unrecognized liability for the underfunded status of our Multiemployer Plan totaled $18.3 million at December 31, 2019 and $3.9 million at December 31, 2018.