Consolidated Statement of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Common stock	Additional paid-in capital	Treasury Stock	Unallocated common stock of ESOP	Retained earnings	Accumulated other comprehensive income (loss)
Balance at Dec. 31, 2018	$ 38,181					$ 39,764	$ (1,583)
Net income (loss)	(471)					(471)
Other comprehensive income (loss)	707						707
Net proceeds from stock offering (4,876,677 shares issued)	20,029	$ 49	$ 19,980
Purchase of ESOP (175,528 shares purchased)	(1,755)				$ (1,755)
Balance at Mar. 31, 2019	56,691	49	19,980		(1,755)	39,293	(876)
Balance at Dec. 31, 2018	38,181					39,764	(1,583)
Net income (loss)	(44)
Balance at Sep. 30, 2019	58,465	49	19,978		(1,702)	39,720	420
Balance at Mar. 31, 2019	56,691	49	19,980		(1,755)	39,293	(876)
Net income (loss)	(9)					(9)
Other comprehensive income (loss)	800						800
ESOP shares committed to be released	33		(2)		35
Balance at Jun. 30, 2019	57,515	49	19,978		(1,720)	39,284	(76)
Net income (loss)	436					436
Other comprehensive income (loss)	496						496
ESOP shares committed to be released	18				18
Balance at Sep. 30, 2019	58,465	49	19,978		(1,702)	39,720	420
Balance at Dec. 31, 2019	58,665	49	19,981		(1,685)	40,213	107
Net income (loss)	287					287
1895 Bancorp of Wisconsin, Inc. common stock held by PyraMax Bank reclassified to treasury stock	(175)			$ (175)
Other comprehensive income (loss)	(124)						(124)
ESOP shares committed to be released	18		1		17
Balance at Mar. 31, 2020	58,671	49	19,982	(175)	(1,668)	40,500	(17)
Balance at Dec. 31, 2019	58,665	49	19,981		(1,685)	40,213	107
Net income (loss)	893
Balance at Sep. 30, 2020	59,640	49	20,076	(1,199)	(1,632)	41,106	1,240
Balance at Mar. 31, 2020	58,671	49	19,982	(175)	(1,668)	40,500	(17)
Net income (loss)	194					194
Other comprehensive income (loss)	1,827						1,827
Repurchase of 1895 Bancorp of Wisconsin, Inc. common stock	(231)			(231)
ESOP shares committed to be released	14		(4)		18
Stock compensation expense	44		44
Balance at Jun. 30, 2020	60,519	49	20,022	(406)	(1,650)	40,694	1,810
Net income (loss)	412					412
Other comprehensive income (loss)	(570)						(570)
Repurchase of 1895 Bancorp of Wisconsin, Inc. common stock	(793)			(793)
ESOP shares committed to be released	17		(1)		18
Stock compensation expense	55		55
Balance at Sep. 30, 2020	$ 59,640	$ 49	$ 20,076	$ (1,199)	$ (1,632)	$ 41,106	$ 1,240