Pension and Other Post Retirement Benefit Plans - Narrative (Details) - USD ($)			12 Months Ended
	Nov. 20, 2015	Mar. 01, 2005	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Percentage of employees covered by plan			15.00%
Minimum participant attained age		55 years
Requisite service period (at least)		10 years
Percentage of the premiums paid by plan participants			100.00%
Release of benefit obligation for plan settlement			$ 4,600,000
Settlement charge			(3,803,000)
Settlement loss recognized			761,000
Accumulated benefit obligation			82,157,000	$ 84,090,000
Minimum required contribution in next fiscal year			$ 0
Requisite service period			1000 hours
Employer percentage contribution			2.00%
Vesting period			5 years
Expense recognized in the period			$ 3,691,000	3,441,000	$ 3,526,000
Curtailment gain			2,157,000
Obligations payable				54,000
Post retirement plan expense			(301,000)	(2,437,000)	(127,000)
Fair value of plan assets			85,213,000	83,557,000	$ 71,396,000
Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets			78,280,000	64,064,000
Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets			$ 6,933,000	$ 19,493,000
Contribution for first 3%
Defined Benefit Plan Disclosure [Line Items]
Amount of discretionary contributions made by employer to defined contribution plan, percent			100.00%
Maximum annual contribution percentage per employee			3.00%
Contribution after first 3%
Defined Benefit Plan Disclosure [Line Items]
Amount of discretionary contributions made by employer to defined contribution plan, percent			50.00%
Maximum annual contribution percentage per employee			3.00%
Ameriana | Pentegra Plan
Defined Benefit Plan Disclosure [Line Items]
Written notice of withdrawal, period	60 days
Minimum
Defined Benefit Plan Disclosure [Line Items]
Age of plan participants			55 years
Minimum | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Maturities of debt securities			15 days	15 days
Maximum
Defined Benefit Plan Disclosure [Line Items]
Age of plan participants			65 years
Maximum | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Maturities of debt securities			8 years 10 months	8 years 11 days
Weighted Average | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Maturities of debt securities			4 years 6 months 12 days	3 years 11 months 20 days