Regulatory Capital (Actual Capital Amounts and Ratios) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Compliance with Regulatory Capital Requirements for Mortgage Companies [Line Items]
Leverage Capital Level, Actual Capital Levels Amount		$ 148,135
Leverage Capital Level, Actual Capital Levels Ratio		9.40%
Leverage Capital Level, Minimum Regulatory Capital Ratios Amount		$ 63,293
Leverage Capital Level, Minimum Regulatory Capital Ratios		4.00%
Description of regulatory requirements, capital adequacy purposes	The minimum capital requirements exclude the capital conservation buffer required to avoid limitations on capital distributions, including dividend payments and certain discretionary bonus payments to executive officers. The capital conservation buffer is being phased in annually, which started January 1, 2016, at the rate of 0.625% per year until fully phased in during 2019. The capital conservation buffer was 1.875% at December 31, 2018. The unrealized gain or loss on available for sale securities is not included in computing regulatory capital. As of December 31, 2018, the Bank is in excess of the capital conversation buffer requirements.
Capital conversion percentage	1.875
MutualFirst Consolidated
Compliance with Regulatory Capital Requirements for Mortgage Companies [Line Items]
Common Equity Tier 1 Capital Level Amount		$ 144,764
Total Risk-Based Capital Level, Actual Capital Levels Amount		160,522
Tier 1 Risk-Based Capital Level, Actual Capital Levels Amount		$ 148,135
Common Equity Tier 1 Capital level, Actual Capital Levels Ratio		12.20%
Total Risk-Based Capital Level, Actual Capital Levels Ratio		13.50%
Tier 1 Risk-Based Capital Level, Actual Capital Levels Ratio		12.50%
Common Equity Tier 1 Risk-Based Capital Level, Minimum Regulatory Capital Ratios Amount		$ 53,249
Total Risk-Based Capital Level, Minimum Regulatory Capital Ratios Amount		94,984
Tier 1 Risk-Based Capital Level, Minimum Regulatory Capital Ratios Amount		$ 71,238
Common Equity Tier 1 Risk-Based Capital Level, Minimum Regulatory Catial Ratios		4.50%
Total Risk-Based Capital Level, Minimum Regulatory Capital Ratios		8.00%
Tier 1 Risk-Based Capital Level, Minimum Regulatory Capital Ratios		6.00%
Tier 1 Capital to Average Total Assets		$ 1,600,000
Risk-Weighted Regulatory Capital Assets		1,200,000
MutualBank
Compliance with Regulatory Capital Requirements for Mortgage Companies [Line Items]
Leverage Capital Level, Actual Capital Levels Amount	$ 184,803	133,515
Common Equity Tier 1 Capital Level Amount	184,803	133,515
Total Risk-Based Capital Level, Actual Capital Levels Amount	198,084	145,902
Tier 1 Risk-Based Capital Level, Actual Capital Levels Amount	$ 184,803	$ 133,515
Leverage Capital Level, Actual Capital Levels Ratio	9.20%	8.40%
Common Equity Tier 1 Capital level, Actual Capital Levels Ratio	12.10%	11.30%
Total Risk-Based Capital Level, Actual Capital Levels Ratio	13.00%	12.30%
Tier 1 Risk-Based Capital Level, Actual Capital Levels Ratio	12.10%	11.30%
Leverage Capital Level, Minimum Regulatory Capital Ratios Amount	$ 80,309	$ 63,254
Common Equity Tier 1 Risk-Based Capital Level, Minimum Regulatory Capital Ratios Amount	68,476	53,407
Total Risk-Based Capital Level, Minimum Regulatory Capital Ratios Amount	121,734	94,946
Tier 1 Risk-Based Capital Level, Minimum Regulatory Capital Ratios Amount	$ 91,301	$ 71,209
Leverage Capital Level, Minimum Regulatory Capital Ratios	4.00%	4.00%
Common Equity Tier 1 Risk-Based Capital Level, Minimum Regulatory Catial Ratios	4.50%	4.50%
Total Risk-Based Capital Level, Minimum Regulatory Capital Ratios	8.00%	8.00%
Tier 1 Risk-Based Capital Level, Minimum Regulatory Capital Ratios	6.00%	6.00%
Leverage Capital Level, Minimum Required To be Considered Well-Capitalized Amount	$ 100,386	$ 79,068
Common Equity Tier 1 Risk-Based Capital Level, Minimum Required To Be Considered Well-Capitalized Amount	98,910	77,143
Total Risk-Based Capital Level, Minimum Required To be Considered Well-Capitalized Amount	152,169	118,682
Tier 1 Risk-Based Capital Level, Minimum Required To be Considered Well-Capitalized Amount	$ 121,735	$ 94,946
Leverage Capital Level, Minimum Required To be Considered Well-Capitalized Ratio	5.00%	5.00%
Common Equity Tier 1 Risk-Based Capital Level, Minimum Required To Be Considered Well-Capitalized Ratio	6.50%	6.50%
Total Risk-Based Capital Level, Minimum Required To be Considered Well-Capitalized Ratio	10.00%	10.00%
Tier 1 Risk-Based Capital Level, Minimum Required To be Considered Well-Capitalized Ratio	8.00%	8.00%
Tier 1 Capital to Average Total Assets	$ 2,000,000
Risk-Weighted Regulatory Capital Assets	$ 1,500,000