Loans Receivable: Schedule of Impaired Financing Receivables (Details) - USD ($) $ in Thousands		Dec. 31, 2018	Dec. 31, 2017
One-to-four family, residential, owner occupied
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	[1]	$ 1,308	$ 1,321
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	[2]	1,477	1,516
Impaired Financing Receivable, with Related Allowance, Recorded Investment	[1]	513	522
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	[2]	560	568
Impaired Financing Receivable, Related Allowance		22	5
Impaired Financing Receivable, Recorded Investment	[1]	1,821	1,843
Impaired Financing Receivable, Unpaid Principal Balance	[2]	2,037	2,084
One-to-four family residential non-owner occupied
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	[1]	2,375	8,409
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	[2]	2,375	8,409
Impaired Financing Receivable, with Related Allowance, Recorded Investment	[1]	3,126	3,310
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance	[2]	3,148	3,332
Impaired Financing Receivable, Related Allowance		37	111
Impaired Financing Receivable, Recorded Investment	[1]	5,501	11,719
Impaired Financing Receivable, Unpaid Principal Balance	[2]	5,523	11,741
Multifamily
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	[1]		1,134
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	[2]		1,134
Impaired Financing Receivable, Related Allowance			0
Impaired Financing Receivable, Recorded Investment	[1]		1,134
Impaired Financing Receivable, Unpaid Principal Balance	[2]		1,134
Commercial Real Estate
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	[1]	2,499	1,065
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	[2]	2,499	1,065
Impaired Financing Receivable, with Related Allowance, Recorded Investment		241	2,129	[1]
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance		241	2,129	[2]
Impaired Financing Receivable, Related Allowance		3	19
Impaired Financing Receivable, Recorded Investment	[1]	2,740	3,194
Impaired Financing Receivable, Unpaid Principal Balance	[2]	2,740	3,194
Consumer
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, Related Allowance		0
Consumer
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	[1]	87	94
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	[2]	141	144
Impaired Financing Receivable, Related Allowance			0
Impaired Financing Receivable, Recorded Investment	[1]	87	94
Impaired Financing Receivable, Unpaid Principal Balance	[2]	141	144
Property total
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with No Related Allowance, Recorded Investment	[1]	6,269	12,023
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance	[2]	6,492	12,268
Impaired Financing Receivable, with Related Allowance, Recorded Investment		3,880	5,961	[1]
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance		3,949	6,029	[2]
Impaired Financing Receivable, Related Allowance		62	135
Impaired Financing Receivable, Recorded Investment	[1]	10,149	17,984
Impaired Financing Receivable, Unpaid Principal Balance	[2]	$ 10,441	$ 18,297

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

[2] (2) Contractual loan principal balance.