Condensed Financial Information (Parent Company Only) (Condensed Statements of Income) (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	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, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income
Interest income from Bank													$ 14	$ 17	$ 29
Total interest and dividend income	$ 13,313	$ 13,049	$ 12,731	$ 12,683	$ 12,893	$ 12,803	$ 12,744	$ 12,738	$ 12,848	$ 13,041	$ 12,877	$ 12,901	51,776	51,178	51,667
Expenses	2,214	2,233	2,191	2,165	2,255	2,163	2,186	2,319	2,644	2,801	2,857	2,922	8,803	8,923	11,224
Income tax benefit													4,578	3,866	4,136
Net Income	3,338	3,225	3,218	2,481	3,661	2,751	2,614	2,020	2,686	2,518	2,157	2,022	12,262	11,046	9,383
Preferred stock dividends and accretion															1,257
Net Income Available to Common Shareholders	$ 3,338	$ 3,225	$ 3,218	$ 2,481	$ 3,661	$ 2,751	$ 2,614	$ 2,020	$ 2,339	$ 2,247	$ 1,879	$ 1,661	12,262	11,046	8,126
MutualFirst Financial, Inc. [Member]
Income
Interest income from Bank													1	1	4
Dividends from Bank													3,600	3,500	30,692
Total interest and dividend income													3,601	3,501	30,696
Expenses													1,182	994	1,036
Income before income tax and equity in undistributed income of the Bank													2,419	2,735	29,843
Income tax benefit													(591)	(337)	(342)
Income before equity in undistributed income (distributions in excess of income) of the Bank													3,010	3,072	30,185
Equity in undistributed income (distributions in excess of income) of the Bank													9,252	7,974	(20,802)
Net Income													12,262	11,046	9,383
Preferred stock dividends and accretion															1,257
Net Income Available to Common Shareholders													$ 12,262	$ 11,046	$ 8,126