Condensed Financial Information (Parent Company Only) (Condensed Statements of Income) (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income
Total interest and dividend income	$ 21,489	$ 20,836	$ 20,621	$ 16,748	$ 15,081	$ 15,026	$ 14,652	$ 14,109	$ 13,943	$ 13,567	$ 13,258	$ 13,034	$ 79,694	$ 58,868	$ 53,802
Expenses	4,995	4,419	4,013	3,164	2,888	2,762	2,565	2,396	2,374	2,330	2,271	2,272	16,591	10,611	9,247
Income tax benefit													2,960	6,793	4,386
Net Income Available to Common Shareholders	$ 5,290	$ 5,402	$ 4,165	$ 4,007	$ 1,460	$ 3,751	$ 3,898	$ 3,206	$ 3,237	$ 3,482	$ 4,157	$ 2,365	18,864	12,315	13,241
MutualFirst Financial, Inc.
Income
Dividends from subsidiaries													6,695	15,100	12,000
Other Income													9
Total interest and dividend income													6,704	15,100	12,000
Expenses													1,922	1,041	976
Income before income tax and equity in undistributed income of subsidiaries													4,782	14,059	11,024
Income tax benefit													(412)	(495)	(399)
Income before equity in undistributed income (distributions in excess of income) of subsidiaries													5,194	14,554	11,423
Equity in undistributed income (distributions in excess of income) of subsidiaries													13,670	(2,239)	1,818
Net Income Available to Common Shareholders													$ 18,864	$ 12,315	$ 13,241