Sch II - Condensed Financial Information on Registrant (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Assets [Abstract]
Fixed maturities - available for sale	$ 7,702,628				$ 7,033,045				$ 7,702,628	$ 7,033,045
Equity securities at fair value (cost: 2019 - $95,269; 2018 - $93,564)	100,228				92,857				100,228	92,857
Short-term investments	11,865				15,713				11,865	15,713
Cash and cash equivalents	17,277				19,035				17,277	19,035	$ 52,696	$ 33,583
Amounts receivable from affiliates	4,357				3,812				4,357	3,812
Accrued investment income	72,332				74,524				72,332	74,524
Current income taxes recoverable	6,427				4,807				6,427	4,807
Other assets	167,940				163,518				167,940	163,518
Assets	10,480,206				9,833,630				10,480,206	9,833,630
Liabilities and stockholders' equity
Amounts payable to affiliates	1,218				1,461				1,218	1,461
Long-term debt payable to non-affiliates	97,000				97,000				97,000	97,000
Liabilities	8,994,290				8,649,371				8,994,290	8,649,371
Preferred stock	3,000				3,000				3,000	3,000
Accumulated other comprehensive income	354,764				91,318				354,764	91,318
Retained earnings	975,260				937,097				975,260	937,097
Total FBL Financial Group, Inc. stockholders' equity	1,485,757				1,184,139				1,485,757	1,184,139
Liabilities and Equity	10,480,206				9,833,630				10,480,206	9,833,630
Revenues:
Net investment income	108,986	$ 101,478	$ 104,894	$ 109,640	83,865	$ 105,757	$ 103,974	$ 101,022	424,998	394,618	415,199
Realized gains (losses) on investments	(2,707)	646	377	9,288	(9,569)	(759)	841	(2,787)	7,604	(12,274)	(3,387)
Other income									17,103	16,181	15,400
Revenues	193,561	184,658	192,906	203,556	158,636	188,111	190,449	182,430	774,681	719,626	737,911
Costs and Expenses [Abstract]
Interest expense									4,850	4,851	4,850
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest									142,781	101,033	144,760
Income Tax Expense (Benefit)									(19,929)	(11,650)	39,983
Net income attributable to FBL Financial Group, Inc.	34,739	$ 25,129	$ 32,298	$ 34,043	6,415	$ 31,010	$ 32,803	$ 23,565	126,209	93,793	187,305
Parent Company
Assets [Abstract]
Investments in subsidiaries (eliminated in consolidation)	1,537,121				1,233,663				1,537,121	1,233,663
Fixed maturities - available for sale	22,483				25,647				22,483	25,647
Equity securities at fair value (cost: 2019 - $95,269; 2018 - $93,564)	7,130				5,262				7,130	5,262
Short-term investments	5,077				5,607				5,077	5,607
Cash and cash equivalents	14,130				12,116				14,130	12,116	23,954	$ 30,803
Accrued investment income	13				18				13	18
Current income taxes recoverable	0				338				0	338
Deferred income tax assets	6,832				6,474				6,832	6,474
Other assets	27,926				13,257				27,926	13,257
Assets	1,626,871				1,307,036				1,626,871	1,307,036
Liabilities and stockholders' equity
Accrued expenses and other liabilities	44,089				25,896				44,089	25,896
Current income taxes	25				0				25	0
Long-term debt payable to non-affiliates	97,000				97,000				97,000	97,000
Liabilities	141,114				122,897				141,114	122,897
Preferred stock	3,000				3,000				3,000	3,000
Accumulated other comprehensive income	354,764				91,318				354,764	91,318
Retained earnings	975,260				937,097				975,260	937,097
Total FBL Financial Group, Inc. stockholders' equity	1,485,757				1,184,139				1,485,757	1,184,139
Liabilities and Equity	1,626,871				1,307,036				1,626,871	1,307,036
Revenues:
Net investment income									1,970	2,381	1,972
Realized gains (losses) on investments									584	(591)	0
Dividends from subsidiaries (eliminated in consolidation)									91,300	91,997	71,500
Other income									8	2	2
Revenues									102,127	102,248	81,280
Costs and Expenses [Abstract]
Interest expense									4,850	4,850	4,850
General and administrative expenses									8,101	8,605	8,408
Total expenses									12,951	13,455	13,258
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest									89,176	88,793	68,022
Income Tax Expense (Benefit)									1,971	2,175	(2,321)
Income (Loss) from Continuing Operations Attributable to Parent									91,147	90,968	65,701
Equity in undistributed income of subsidiary									35,062	2,825	121,604
Net income attributable to FBL Financial Group, Inc.									126,209	93,793	187,305
Common Class A
Liabilities and stockholders' equity
Common stock, without par value	152,661				152,652				152,661	152,652
Common Class A | Parent Company
Liabilities and stockholders' equity
Common stock, without par value	152,661				152,652				152,661	152,652
Common Class B
Liabilities and stockholders' equity
Common stock, without par value	72				72				72	72
Common Class B | Parent Company
Liabilities and stockholders' equity
Common stock, without par value	72				72				72	72
Affiliated Entity | Parent Company
Assets [Abstract]
Amounts receivable from affiliates	2,382				935				2,382	935
Subsidiaries | Parent Company
Assets [Abstract]
Amounts receivable from affiliates	3,777				3,719				3,777	3,719
Liabilities and stockholders' equity
Amounts payable to affiliates	$ 0				$ 1				0	1
Management Service | Affiliated Entity | Parent Company
Revenues:
Revenue from Contract with Customer, Excluding Assessed Tax									2,000	2,001	2,001
Management Service | Subsidiaries | Parent Company
Revenues:
Revenue from Contract with Customer, Excluding Assessed Tax									$ 6,265	$ 6,458	$ 5,805