Quarterly Financial Information (unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Premiums and product charges	$ 78,428	$ 73,533	$ 78,632	$ 78,249	$ 76,532	$ 76,575	$ 77,164	$ 75,269
Net investment income	101,549	103,514	100,722	98,385	99,005	95,882	97,489	98,773	$ 404,170	$ 391,149	$ 382,082
Realized gains (losses) on investments	517	621	(2,294)	(607)	3,553	(506)	7,808	(366)	(1,763)	10,489	2,938
Revenues	184,179	181,284	181,285	179,666	182,624	175,494	186,745	177,946	726,414	722,809	692,939
Net income attributable to FBL Financial Group, Inc.	$ 26,880	$ 30,017	$ 24,380	$ 25,946	$ 30,905	$ 26,659	$ 32,372	$ 23,591	$ 107,223	$ 113,527	$ 109,941
Earnings per common share	$ 1.07	$ 1.20	$ 0.97	$ 1.04	$ 1.24	$ 1.07	$ 1.30	$ 0.95	$ 4.29	$ 4.55	$ 4.42
Earnings per common share - assuming dilution	$ 1.07	$ 1.20	$ 0.97	$ 1.04	$ 1.23	$ 1.06	$ 1.29	$ 0.94	$ 4.28	$ 4.53	$ 4.39