Condensed Financial Information (Parent Company Only) (Condensed Statements of Cash Flows) (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
Operating Activities
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
Item not requiring cash
Deferred income tax													1,537	1,926	1,087
Other													143	143	474
Net cash provided by operating activities													18,551	15,933	12,010
Investing Activities
Net cash used in investing activities													(76,606)	(67,532)	(21,760)
Financing Activities
Repayments of other borrowings													(5,312)	(759)	(759)
Cash dividends													(4,284)	(3,550)	(2,297)
Proceeds from stock options exercised													976	2,011	1,347
Net cash provided by financing activities													64,000	42,939	14,040
Net Change in Cash and Cash Equivalents													5,945	(8,660)	4,290
Cash and Cash Equivalents, Beginning of Period				20,915				29,575				25,285	20,915	29,575	25,285
Cash and Cash Equivalents, End of Period	26,860				20,915				29,575				26,860	20,915	29,575
MutualFirst Financial, Inc. [Member]
Operating Activities
Net income													13,241	12,262	11,046
Item not requiring cash
Deferred income tax													200	(102)	159
(Equity in undistributed income) distributions in excess of income of subsidiary													(1,818)	(9,252)	(8,202)
Other													(183)	13	19
Net cash provided by operating activities													11,440	2,921	3,022
Investing Activities
Investment in subsidiary													(100)	(250)
Net cash used in investing activities													(100)	(250)
Financing Activities
Repayments of other borrowings													(5,312)	(759)	(759)
Stock repurchased													(4,354)
Cash dividends													(4,284)	(3,550)	(2,297)
Proceeds from stock options exercised													976	2,011	1,347
Net cash provided by financing activities													(12,974)	(2,298)	(1,709)
Net Change in Cash and Cash Equivalents													(1,634)	373	1,313
Cash and Cash Equivalents, Beginning of Period				$ 2,756				$ 2,383				$ 1,070	2,756	2,383	1,070
Cash and Cash Equivalents, End of Period	$ 1,122				$ 2,756				$ 2,383				$ 1,122	$ 2,756	$ 2,383