Condensed Financial Information (Parent Company Only) (Condensed Statements of Comprehensive 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
Condensed Financial Statements, Captions [Line Items]
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
Other Comprehensive Income (Loss)
Net unrealized holding gain (loss) on securities available for sale													(3,297)	(1,186)	8,921
Net unrealized gain on securities available-for-sale for which a portion of an other-than-temporary impairment has been recognized in income													39	12	381
Less: Reclassification adjustment for realized gains included in net included in net income													(1,023)	(436)	(313)
Net unrealized gain on derivative used for cash flow hedges													1	108	150
Net unrealized gain (loss) related to defined benefit plan													62	77	(209)
Other Comprehensive Income (Loss), before Tax													(4,218)	(1,425)	8,930
Income tax (expense) benefit related to other comprehensive income													1,474	537	(3,137)
Other comprehensive income (loss)													(2,744)	(888)	5,793
Comprehensive income													10,497	11,374	16,839
MutualFirst Financial, Inc. [Member]
Condensed Financial Statements, Captions [Line Items]
Net income													13,241	12,262	11,046
Other Comprehensive Income (Loss)
Net unrealized holding gain (loss) on securities available for sale													(3,297)	(1,186)	8,921
Net unrealized gain on securities available-for-sale for which a portion of an other-than-temporary impairment has been recognized in income													39	12	381
Less: Reclassification adjustment for realized gains included in net included in net income													(1,023)	(436)	(313)
Net unrealized gain on derivative used for cash flow hedges													1	108	150
Net unrealized gain (loss) related to defined benefit plan													62	77	(209)
Other Comprehensive Income (Loss), before Tax													(4,218)	(1,425)	8,930
Income tax (expense) benefit related to other comprehensive income													1,474	537	(3,137)
Other comprehensive income (loss)													(2,744)	(888)	5,793
Comprehensive income													$ 10,497	$ 11,374	$ 16,839