Loans Receivable: Schedule of Impaired Financing Receivables (Details) - USD ($) $ in Thousands		Dec. 31, 2019	Dec. 31, 2018
One-to-four family, residential, owner occupied
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	[1]	$ 437	$ 1,308
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	[2]	582	1,477
Impaired Financing Receivable, with Related Allowance, Recorded Investment	[1]	505	513
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	[2]	552	560
Impaired Financing Receivable, Related Allowance		13	22
Impaired Financing Receivable, Recorded Investment	[1]	942	1,821
Impaired Financing Receivable, Unpaid Principal Balance	[2]	1,134	2,037
One-to-four family residential non-owner occupied
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	[1]	1,486	2,375
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	[2]	1,486	2,375
Impaired Financing Receivable, with Related Allowance, Recorded Investment	[1]	1,647	3,126
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	[2]	1,647	3,148
Impaired Financing Receivable, Related Allowance		18	37
Impaired Financing Receivable, Recorded Investment	[1]	3,133	5,501
Impaired Financing Receivable, Unpaid Principal Balance	[2]	3,133	5,523
Multifamily
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	[1]	2,105
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	[2]	2,105
Impaired Financing Receivable, Related Allowance		0
Impaired Financing Receivable, Recorded Investment	[1]	2,105
Impaired Financing Receivable, Unpaid Principal Balance	[2]	2,105
Commercial Real Estate
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	[1]	1,266	2,499
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	[2]	1,266	2,499
Impaired Financing Receivable, with Related Allowance, Recorded Investment	[1]		241
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	[2]		241
Impaired Financing Receivable, Related Allowance		0	3
Impaired Financing Receivable, Recorded Investment	[1]	1,266	2,740
Impaired Financing Receivable, Unpaid Principal Balance	[2]	1,266	2,740
Construction Land Development
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	[1]	12,524
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	[2]	15,650
Impaired Financing Receivable, Related Allowance		0
Impaired Financing Receivable, Recorded Investment	[1]	12,524
Impaired Financing Receivable, Unpaid Principal Balance	[2]	15,650
Consumer
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	[1]		87
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	[2]		141
Impaired Financing Receivable, Related Allowance			0
Impaired Financing Receivable, Recorded Investment	[1]		87
Impaired Financing Receivable, Unpaid Principal Balance	[2]		141
Property total
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	[1]	17,818	6,269
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	[2]	21,089	6,492
Impaired Financing Receivable, with Related Allowance, Recorded Investment		2,152	3,880	[1]
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance		2,199	3,949	[2]
Impaired Financing Receivable, Related Allowance		31	62
Impaired Financing Receivable, Recorded Investment	[1]	19,970	10,149
Impaired Financing Receivable, Unpaid Principal Balance	[2]	$ 23,288	$ 10,441

[1] (1) Represents the loan balance less charge-offs.

[2] (2) Contractual loan principal balance.