Loans - Recorded investment in loans based on impairment method (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning balance	$ 2,446	$ 2,359	$ 2,406	$ 2,361
Charge offs	(5)	0	(5)	(2)
Recoveries	6	3	6	3
Provisions	115	25	155	25
Ending balance	2,562	2,387	2,562	2,387
Individually evaluated for impairment	0		0		$ 0
Collectively evaluated for impairment	2,562		2,562		2,406
Loans individually evaluated for impairment	3,277		3,277		3,440
Loans collectively evaluated for impairment	307,061		307,061		251,172
Total ending loans balance	310,338		310,338		254,612
Real estate loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Ending balance		1,314		1,314
Commercial Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning balance	166	181	145	187
Charge offs		0
Recoveries
Provisions	45	(13)	66	(19)
Ending balance	211	168	211	168
Individually evaluated for impairment	0		0		0
Collectively evaluated for impairment	211		211		145
Loans individually evaluated for impairment					237
Loans collectively evaluated for impairment	33,644		33,644		23,975
Total ending loans balance	33,644		33,644		24,212
Consumer Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning balance	84	66	66	64
Charge offs		0		(2)
Recoveries		3		3
Provisions	15	5	33	9
Ending balance	99	74	99	74
Individually evaluated for impairment	0		0		0
Collectively evaluated for impairment	99		99		66
Loans individually evaluated for impairment
Loans collectively evaluated for impairment	9,251		9,251		6,431
Total ending loans balance	9,251		9,251		6,431
One To Four Family [Member] | Real estate loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning balance	1,332	1,279	1,355	1,300
Charge offs		0
Recoveries	6		6
Provisions	166	35	143	14
Ending balance	1,504	1,314	1,504	1,314
Individually evaluated for impairment	0		0		0
Collectively evaluated for impairment	1,504		1,504		1,355
Loans individually evaluated for impairment	120		120		14
Loans collectively evaluated for impairment	152,660		152,660		127,740
Total ending loans balance	152,780		152,780		127,754
Multifamily [Member] | Real estate loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning balance	16	26	19	27
Charge offs		0
Recoveries
Provisions	(2)	(6)	(5)	(7)
Ending balance	14	20	14	20
Individually evaluated for impairment	0		0		0
Collectively evaluated for impairment	14		14		19
Loans individually evaluated for impairment
Loans collectively evaluated for impairment	3,059		3,059		3,730
Total ending loans balance	3,059		3,059		3,730
Commercial [Member] | Real estate loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning balance	732	739	712	746
Charge offs		0
Recoveries
Provisions	(140)	(12)	(120)	(19)
Ending balance	592	727	592	727
Individually evaluated for impairment	0		0		0
Collectively evaluated for impairment	592		592		712
Loans individually evaluated for impairment	3,157		3,157		3,189
Loans collectively evaluated for impairment	88,275		88,275		73,778
Total ending loans balance	91,432		91,432		76,967
Construction [Member] | Real estate loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning balance	116	68	109	37
Charge offs	(5)	0	(5)
Recoveries
Provisions	31	16	38	47
Ending balance	142	$ 84	142	$ 84
Individually evaluated for impairment	0		0		0
Collectively evaluated for impairment	142		142		109
Loans individually evaluated for impairment
Loans collectively evaluated for impairment	20,172		20,172		15,518
Total ending loans balance	$ 20,172		$ 20,172		$ 15,518