Document and Entity Information	6 Months Ended
	Jun. 30, 2019 shares
Document and Entity Information [Abstract]
Document Type	10-Q
Document Period End Date	Jun. 30, 2019
Amendment Flag	false
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Trading Symbol	BCOW
Entity Registrant Name	1895 Bancorp of Wisconsin, Inc.
Entity Central Index Key	0001751692
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Address, State or Province	WI
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common Stock
Security Exchange Name	NASDAQ
Entity Common Stock, Shares Outstanding	4,876,677