Loans Receivable: Schedule of Allowance for Loan and Lease Losses, Roll Forward (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Allowance for Loan and Lease Losses [Roll Forward]
Loans and Leases Receivable, Allowance, Beginning Balance		$ 13,347
(Recapture) provision		(300)	$ (4,000)
Loans and Leases Receivable, Allowance, Ending Balance		13,218	13,347
Loans receivable allowance for loan losses		13,218	13,347	$ 13,218	$ 13,347
One-to-four family residential
Allowance for Loan and Lease Losses [Roll Forward]
Loans and Leases Receivable, Allowance, Beginning Balance		3,387	2,837
Charge-offs		0	0
Recoveries		73	4,279
(Recapture) provision		(426)	(3,729)
Loans and Leases Receivable, Allowance, Ending Balance		3,034	3,387
Loans receivable allowance for loan losses		3,034	3,387	3,034	3,387
Total Loans				372,528	341,966
One-to-four family residential | General Reserve
Allowance for Loan and Lease Losses [Roll Forward]
Loans and Leases Receivable, Allowance, Beginning Balance		3,328
Loans and Leases Receivable, Allowance, Ending Balance		3,003	3,328
Loans receivable allowance for loan losses		3,003	3,328	3,003	3,328
Total Loans	[1]			368,453	334,644
One-to-four family residential | Specific Reserve
Allowance for Loan and Lease Losses [Roll Forward]
Loans and Leases Receivable, Allowance, Beginning Balance		59
Loans and Leases Receivable, Allowance, Ending Balance		31	59
Loans receivable allowance for loan losses		31	59	31	59
Total Loans	[2]			4,075	7,322
Multifamily
Allowance for Loan and Lease Losses [Roll Forward]
Loans and Leases Receivable, Allowance, Beginning Balance		1,680	1,820
Charge-offs		0	0
Recoveries		45	0
(Recapture) provision		(118)	(140)
Loans and Leases Receivable, Allowance, Ending Balance		1,607	1,680
Loans receivable allowance for loan losses		1,607	1,680	1,607	1,680
Total Loans				172,915	169,355
Multifamily | General Reserve
Allowance for Loan and Lease Losses [Roll Forward]
Loans and Leases Receivable, Allowance, Beginning Balance		1,680
Loans and Leases Receivable, Allowance, Ending Balance		1,607	1,680
Loans receivable allowance for loan losses		1,607	1,680	1,607	1,680
Total Loans	[1]			170,810	169,355
Multifamily | Specific Reserve
Allowance for Loan and Lease Losses [Roll Forward]
Loans and Leases Receivable, Allowance, Beginning Balance		0
Loans and Leases Receivable, Allowance, Ending Balance		0	0
Loans receivable allowance for loan losses		0	0	0	0
Total Loans	[2]			2,105	0
Commercial Real Estate
Allowance for Loan and Lease Losses [Roll Forward]
Loans and Leases Receivable, Allowance, Beginning Balance		4,777	4,418
Charge-offs		0	0
Recoveries		0	14
(Recapture) provision		(218)	345
Loans and Leases Receivable, Allowance, Ending Balance		4,559	4,777
Loans receivable allowance for loan losses		4,559	4,777	4,559	4,777
Total Loans				395,152	373,798
Commercial Real Estate | General Reserve
Allowance for Loan and Lease Losses [Roll Forward]
Loans and Leases Receivable, Allowance, Beginning Balance		4,774
Loans and Leases Receivable, Allowance, Ending Balance		4,559	4,774
Loans receivable allowance for loan losses		4,559	4,774	4,559	4,774
Total Loans	[1]			393,886	371,058
Commercial Real Estate | Specific Reserve
Allowance for Loan and Lease Losses [Roll Forward]
Loans and Leases Receivable, Allowance, Beginning Balance		3
Loans and Leases Receivable, Allowance, Ending Balance		0	3
Loans receivable allowance for loan losses		0	3	0	3
Total Loans	[2]			1,266	2,740
Construction Land Development
Allowance for Loan and Lease Losses [Roll Forward]
Loans and Leases Receivable, Allowance, Beginning Balance		2,331	2,816
Charge-offs		0	0
Recoveries		0	171
(Recapture) provision		(109)	(656)
Loans and Leases Receivable, Allowance, Ending Balance		2,222	2,331
Loans receivable allowance for loan losses		2,222	2,331	2,222	2,331
Total Loans				113,665	108,854
Construction Land Development | General Reserve
Allowance for Loan and Lease Losses [Roll Forward]
Loans and Leases Receivable, Allowance, Beginning Balance		2,331
Loans and Leases Receivable, Allowance, Ending Balance		2,222	2,331
Loans receivable allowance for loan losses		2,222	2,331	2,222	2,331
Total Loans	[1]			101,141	108,854
Construction Land Development | Specific Reserve
Allowance for Loan and Lease Losses [Roll Forward]
Loans and Leases Receivable, Allowance, Beginning Balance		0
Loans and Leases Receivable, Allowance, Ending Balance		0	0
Loans receivable allowance for loan losses		0	0	0	0
Total Loans	[2]			12,524	0
Business
Allowance for Loan and Lease Losses [Roll Forward]
Loans and Leases Receivable, Allowance, Beginning Balance		936	694
Charge-offs		0	0
Recoveries		0	0
(Recapture) provision		204	242
Loans and Leases Receivable, Allowance, Ending Balance		1,140	936
Loans receivable allowance for loan losses		1,140	936	1,140	936
Total Loans				37,779	30,486
Business | General Reserve
Allowance for Loan and Lease Losses [Roll Forward]
Loans and Leases Receivable, Allowance, Beginning Balance		936
Loans and Leases Receivable, Allowance, Ending Balance		1,140	936
Loans receivable allowance for loan losses		1,140	936	1,140	936
Total Loans	[1]			37,779	30,486
Business | Specific Reserve
Allowance for Loan and Lease Losses [Roll Forward]
Loans and Leases Receivable, Allowance, Beginning Balance		0
Loans and Leases Receivable, Allowance, Ending Balance		0	0
Loans receivable allowance for loan losses		0	0	0	0
Total Loans	[2]			0	0
Consumer
Allowance for Loan and Lease Losses [Roll Forward]
Loans and Leases Receivable, Allowance, Beginning Balance		236	297
Charge-offs		0	0
Recoveries		53	1
(Recapture) provision		367	(62)
Loans and Leases Receivable, Allowance, Ending Balance		656	236
Loans receivable allowance for loan losses		656	236	656	236
Total Loans				30,199	12,970
Consumer | General Reserve
Allowance for Loan and Lease Losses [Roll Forward]
Loans and Leases Receivable, Allowance, Beginning Balance		236
Loans and Leases Receivable, Allowance, Ending Balance		656	236
Loans receivable allowance for loan losses		656	236	656	236
Total Loans	[1]			30,199	12,883
Consumer | Specific Reserve
Allowance for Loan and Lease Losses [Roll Forward]
Loans and Leases Receivable, Allowance, Beginning Balance		0
Loans and Leases Receivable, Allowance, Ending Balance		0	0
Loans receivable allowance for loan losses		0	0	0	0
Total Loans	[2]			0	87
Property total
Allowance for Loan and Lease Losses [Roll Forward]
Loans and Leases Receivable, Allowance, Beginning Balance		13,347	12,882
Charge-offs		0	0
Recoveries		171	4,465
(Recapture) provision		(300)	(4,000)
Loans and Leases Receivable, Allowance, Ending Balance		13,218	13,347
Loans receivable allowance for loan losses		13,218	13,347	13,218	13,347
Total Loans				1,122,238	1,037,429
Property total | General Reserve
Allowance for Loan and Lease Losses [Roll Forward]
Loans and Leases Receivable, Allowance, Beginning Balance		13,285
Loans and Leases Receivable, Allowance, Ending Balance		13,187	13,285
Loans receivable allowance for loan losses		13,187	13,285	13,187	13,285
Total Loans	[1]			1,102,268	1,027,280
Property total | Specific Reserve
Allowance for Loan and Lease Losses [Roll Forward]
Loans and Leases Receivable, Allowance, Beginning Balance		62
Loans and Leases Receivable, Allowance, Ending Balance		31	62
Loans receivable allowance for loan losses		$ 31	$ 62	31	62
Total Loans	[2]			$ 19,970	$ 10,149

[1] Loans collectively evaluated for general reserves.

[2] Loans individually evaluated for specific reserves.