Condensed Financial Information (Parent Company Only) (Condensed Statements of Income) (Details) - USD ($) $ 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, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income
Interest income from Bank													$ 76	$ 14	$ 17
Total interest and dividend income	$ 13,943	$ 13,567	$ 13,258	$ 13,034	$ 13,313	$ 13,049	$ 12,731	$ 12,683	$ 12,893	$ 12,803	$ 12,744	$ 12,738	53,802	51,776	51,178
Expenses	2,374	2,330	2,271	2,272	2,214	2,233	2,191	2,165	2,255	2,163	2,186	2,319	9,247	8,803	8,923
Income tax benefit													4,386	4,578	3,866
Net Income	$ 3,237	$ 3,482	$ 4,157	$ 2,365	$ 3,338	$ 3,225	$ 3,218	$ 2,481	$ 3,661	$ 2,751	$ 2,614	$ 2,020	13,241	12,262	11,046
Net Income Available to Common Shareholders													13,241	12,262
MutualFirst Financial, Inc. [Member]
Income
Interest income from Bank														1	1
Dividends from subsidiaries													12,000	3,600	3,500
Total interest and dividend income													12,000	3,601	3,501
Expenses													976	1,182	994
Income before income tax and equity in undistributed income of subsidiaries													11,024	2,419	2,507
Income tax benefit													(399)	(591)	(337)
Income before equity in undistributed income (distributions in excess of income) of subsidiaries													11,423	3,010	2,844
Equity in undistributed income (distributions in excess of income) of subsidiaries													1,818	9,252	8,202
Net Income													$ 13,241	$ 12,262	$ 11,046