Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2019

Stockholders' Equity Note [Abstract]

Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations

The following table presents a reconciliation of GAAP capital and regulatory capital and information as to the Bank's capital levels at the dates presented:

	Actual				For capital adequacy purposes (1)			To be well capitalized under prompt corrective action provisions
	Amount		Ratio		Amount		Ratio	Amount		Ratio
	(Dollars in thousands)
December 31, 2019:
Tier 1 leverage capital ratio
Millington Bank	$	61,991	10.70	%	$	23,164	≥4.00	$	28,955	≥5.00
MSB Financial Corp.	65,375		11.33		N/A		N/A	N/A		N/A
Common equity tier 1 capital ratio
Millington Bank	61,991		11.43		24,396		≥4.50	35,239		≥6.50
MSB Financial Corp.	65,375		12.06		N/A		N/A	N/A		N/A
Tier 1 capital ratio
Millington Bank	61,991		11.43		32,528		≥6.00	43,371		≥8.00
MSB Financial Corp.	65,375		12.06		N/A		N/A	N/A		N/A
Total capital ratio
Millington Bank	67,801		12.51		43,371		≥8.00	54,213		≥10.00
MSB Financial Corp.	71,185		13.13		N/A		N/A	N/A		N/A

(1) Amounts and ratios do not include the capital conservation buffer.

	Actual				For capital adequacy purposes (1)			To be well capitalized under prompt corrective action provisions
	Amount		Ratio		Amount		Ratio	Amount		Ratio
	(Dollars in thousands)
December 31, 2018:
Tier 1 leverage capital ratio
Millington Bank	$	61,740	10.71	%	$	23,052	≥4.00	$	28,816	≥5.00
MSB Financial Corp.	66,646		11.56		N/A		N/A	N/A		N/A
Common equity tier 1 capital ratio
Millington Bank	61,740		11.90		23,351		≥4.50	33,729		≥6.50
MSB Financial Corp.	66,646		12.84		N/A		N/A	N/A		N/A
Tier 1 capital ratio
Millington Bank	61,740		11.90		31,134		≥6.00	41,512		≥8.00
MSB Financial Corp.	66,646		12.84		N/A		N/A	N/A		N/A
Total capital ratio
Millington Bank	67,467		13.00		41,512		≥8.00	51,891		≥10.00
MSB Financial Corp.	72,373		13.95		N/A		N/A	N/A		N/A

(1) Amounts and ratios do not include the capital conservation buffer.