Loans Receivable: Non-performing Loans, Foregone interest, and loans committed (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, after allowance	$ 1,182,159	$ 1,119,536
One-to-four family residential
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, after allowance	475,836	385,116
Multifamily
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, after allowance	126,895	130,146
Commercial Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, after allowance	407,882	419,417
Construction Land Development
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, after allowance	78,120	93,455
Business
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, after allowance	31,371	46,590
Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, after allowance	62,055	44,812
One-to-four family, residential, owner occupied
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, after allowance	233,785	185,320
One-to-four family residential non-owner occupied
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, after allowance	242,051	199,796
Performing Financing Receivable
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, after allowance	1,181,966	1,119,536
Performing Financing Receivable | One-to-four family residential
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, after allowance	475,836	385,116
Performing Financing Receivable | Multifamily
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, after allowance	126,895	130,146
Performing Financing Receivable | Commercial Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, after allowance	407,882	419,417
Performing Financing Receivable | Construction Land Development
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, after allowance	78,120	93,455
Performing Financing Receivable | Business
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, after allowance	31,371	46,590
Performing Financing Receivable | Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, after allowance	61,862	44,812
Performing Financing Receivable | One-to-four family, residential, owner occupied
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, after allowance	233,800	185,300
Performing Financing Receivable | One-to-four family residential non-owner occupied
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, after allowance	242,100	199,800
Nonperforming Financing Receivable
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, after allowance	193	0
Nonperforming Financing Receivable | One-to-four family residential
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, after allowance	0	0
Nonperforming Financing Receivable | Multifamily
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, after allowance	0	0
Nonperforming Financing Receivable | Commercial Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, after allowance	0	0
Nonperforming Financing Receivable | Construction Land Development
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, after allowance	0	0
Nonperforming Financing Receivable | Business
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, after allowance	0	0
Nonperforming Financing Receivable | Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Financing receivable, after allowance	$ 193	$ 0