Loans Receivable: Average Recorded Investment and Interest Income Recognized (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Accounts, Notes, Loans and Financing Receivable
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	$ 10,691	$ 10,187	$ 9,216	$ 10,799
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized	308	177	528	378
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	2,525	4,996	2,976	5,317
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized	31	51	62	117
Impaired Financing Receivable, Average Recorded Investment	13,216	15,183	12,192	16,116
Impaired Financing Receivable, Interest Income, Accrual Method	339	228	590	495
One-to-four family, residential, owner occupied
Accounts, Notes, Loans and Financing Receivable
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	843	1,180	998	1,227
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized	15	18	30	36
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	510	519	511	520
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized	9	9	17	18
Impaired Financing Receivable, Average Recorded Investment	1,353	1,699	1,509	1,747
Impaired Financing Receivable, Interest Income, Accrual Method	24	27	47	54
One to four family residential non owner occupied
Accounts, Notes, Loans and Financing Receivable
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	1,863	6,136	2,034	6,894
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized	26	99	52	221
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	2,015	3,232	2,385	3,258
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized	22	35	45	82
Impaired Financing Receivable, Average Recorded Investment	3,878	9,368	4,419	10,152
Impaired Financing Receivable, Interest Income, Accrual Method	48	134	97	303
Multifamily
Accounts, Notes, Loans and Financing Receivable
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment		1,125		1,128
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized		18		37
Impaired Financing Receivable, Average Recorded Investment		1,125		1,128
Impaired Financing Receivable, Interest Income, Accrual Method		18		37
Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	2,149	1,654	2,265	1,457
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized	38	40	76	80
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment	0	1,245	80	1,539
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized	0	7	0	17
Impaired Financing Receivable, Average Recorded Investment	2,149	2,899	2,345	2,996
Impaired Financing Receivable, Interest Income, Accrual Method	38	47	76	97
Consumer Loan
Accounts, Notes, Loans and Financing Receivable
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	44	92	58	93
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized	1	2	2	4
Impaired Financing Receivable, Average Recorded Investment	44	92	58	93
Impaired Financing Receivable, Interest Income, Accrual Method	1	$ 2	2	$ 4
Construction Land Development
Accounts, Notes, Loans and Financing Receivable
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment	5,792		3,861
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized	228		368
Impaired Financing Receivable, Average Recorded Investment	5,792		3,861
Impaired Financing Receivable, Interest Income, Accrual Method	$ 228		$ 368