Note 2: Investments in Securities: Mortgage-backed securities portfolio (Details) $ in Thousands	Dec. 31, 2017 USD ($)
Adjustable Rate Residential Mortgage
Mortgage-backed Securities Available-for-sale, Fair Value Disclosure	$ 105,600
Fixed Rate Residential Mortgage
Mortgage-backed Securities Available-for-sale, Fair Value Disclosure	16,900
Federal Home Loan Mortgage Corporation (FHLMC) Insured Loans
Mortgage-backed Securities Available-for-sale, Fair Value Disclosure	47,300
Federal National Mortgage Association (FNMA) Insured Loans
Mortgage-backed Securities Available-for-sale, Fair Value Disclosure	43,600
Government National Mortgage Association (GNMA) Insured Loans
Mortgage-backed Securities Available-for-sale, Fair Value Disclosure	$ 31,600