Earnings per Share (Details) - USD ($) $ / shares in Units, $ 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
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
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
Dividends on preferred stock									150	150	150
Income available to common stockholders									$ 126,059	$ 93,643	$ 187,155
Weighted Average Number of Shares Outstanding, Basic									24,760,541	24,932,189	25,038,334
Weighted Average Number Diluted Shares Outstanding Adjustment									10,134	12,412	19,111
Weighted Average Number of Shares Outstanding, Diluted									24,770,675	24,944,601	25,057,445
Earnings per common share	$ 1.40	$ 1.01	$ 1.30	$ 1.37	$ 0.26	$ 1.24	$ 1.31	$ 0.94	$ 5.09	$ 3.76	$ 7.47
Earnings per common share - assuming dilution	$ 1.40	$ 1.01	$ 1.30	$ 1.37	$ 0.26	$ 1.24	$ 1.31	$ 0.94	$ 5.09	$ 3.75	$ 7.47