Summary of Significant Accounting Policies (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended	12 Months Ended
	Jan. 16, 2020	Mar. 31, 2020	Dec. 31, 2019
Common stock, outstanding (in shares)		7,704,875	7,702,478
Stock issued during period, shares	4,268,570
Issuance of common stock, net of issuance costs	$ 37,900
Purchase of ESOP shares (in shares)	341,485	341,485
Sale of stock, price per share	$ 10.00
Direct costs of the conversion and public offering		$ 1,200
Unrecognized tax benefits, income tax penalties and interest expense		$ 0
Owned by Public [Member]
Common stock, outstanding (in shares)			3,436,424
Percentage of common stock outstanding to eligible Members			44.60%
FFBW Community Foundation [Member]
Common stock, outstanding (in shares)			29,325
FFBW, MHC [Member]
Common stock, outstanding (in shares)			4,266,054
Stock issued during period, shares	3,436,430
Percentage of shares held by Mutual Holding Company			55.40%