Segment Information Segment assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Segment assets	$ 9,324,595	$ 8,946,257
Unrealized Gains on assets in AOCI	241,539	185,747
Assets	9,566,134	9,132,004
Goodwill	9,900	9,900
Annuity
Segment Reporting Information [Line Items]
Segment assets	4,452,878	4,209,627
Goodwill	3,900	3,900
Life Insurance
Segment Reporting Information [Line Items]
Segment assets	3,256,306	3,112,756
Goodwill	6,100	6,100
Corporate and Other
Segment Reporting Information [Line Items]
Segment assets	1,615,411	1,623,874
Farm Bureau Property & Casualty insurance company [Member]
Segment Reporting Information [Line Items]
Operating Leases, Income Statement, Lease Revenue Depreciation and Amortization	$ 4,400	$ 4,100	$ 3,100