Loans Receivable: Financing Receivables, Aging of loans (Details) - USD ($)	Mar. 31, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing	$ 0	$ 0
Total Loans	1,066,220,000	1,037,429,000
One-to-four family, residential, owner occupied
Total	107,000	495,000
Current	194,541,000	193,646,000
Total Loans	194,648,000	194,141,000
One to four family residential non owner occupied
Total	166,000	0
Current	156,518,000	147,825,000
Total Loans	156,684,000	147,825,000
Multifamily
Total	0	0
Current	167,843,000	169,355,000
Total Loans	167,843,000	169,355,000
Commercial Real Estate
Total	0	326,000
Current	384,686,000	373,472,000
Total Loans	384,686,000	373,798,000
Construction Land Development
Total	0	0
Current	114,510,000	108,854,000
Total Loans	114,510,000	108,854,000
Real Estate, Total
Total	273,000	821,000
Current	1,018,098,000	993,152,000
Total Loans	1,018,371,000	993,973,000
Business
Total	0	0
Current	33,513,000	30,486,000
Total Loans	33,513,000	30,486,000
Consumer
Total	44,000	0
Current	14,292,000	12,970,000
Total Loans	14,336,000	12,970,000
Property total
Total	317,000	821,000
Current	1,065,903,000	1,036,608,000
Total Loans	1,066,220,000	1,037,429,000
Financing Receivables, 30 to 59 Days Past Due [Member] | One-to-four family, residential, owner occupied
Total	107,000	223,000
Financing Receivables, 30 to 59 Days Past Due [Member] | One to four family residential non owner occupied
Total	166,000	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Multifamily
Total	0	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Real Estate
Total	0	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Construction Land Development
Total	0	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Real Estate, Total
Total	273,000	223,000
Financing Receivables, 30 to 59 Days Past Due [Member] | Business
Total	0	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer
Total	44,000	0
Financing Receivables, 30 to 59 Days Past Due [Member] | Property total
Total	317,000	223,000
Financing Receivables, 60 to 89 Days Past Due [Member] | One-to-four family, residential, owner occupied
Total	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | One to four family residential non owner occupied
Total	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Multifamily
Total	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Real Estate
Total	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Construction Land Development
Total	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Real Estate, Total
Total	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Business
Total	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer
Total	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] | Property total
Total	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | One-to-four family, residential, owner occupied
Total	0	272,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | One to four family residential non owner occupied
Total	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Multifamily
Total	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Real Estate
Total	0	326,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Construction Land Development
Total	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Real Estate, Total
Total	0	598,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Business
Total	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer
Total	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Property total
Total	$ 0	$ 598,000