Note 14: Disclosures About Fair Value of Financial Instruments: Fair Value Measurement, Policy: Fair Value, Assets Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises
Recurring Assets, Fair Value Disclosure	$ 121,525	$ 122,533
Collateralized Mortgage Obligations
Recurring Assets, Fair Value Disclosure	17,384
US States and Political Subdivisions Debt Securities
Recurring Assets, Fair Value Disclosure	52,342	56,646
Interest rate derivative asset
Recurring Assets, Fair Value Disclosure	1,453	981
Interest rate derivative liability
Recurring Assets, Fair Value Disclosure	(1,448)	(1,030)
Fair Value, Inputs, Level 1 | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises
Recurring Assets, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 1 | Collateralized Mortgage Obligations
Recurring Assets, Fair Value Disclosure	0
Fair Value, Inputs, Level 1 | US States and Political Subdivisions Debt Securities
Recurring Assets, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 1 | Interest rate derivative asset
Recurring Assets, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 1 | Interest rate derivative liability
Recurring Assets, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 2 | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises
Recurring Assets, Fair Value Disclosure	121,525	122,533
Fair Value, Inputs, Level 2 | Collateralized Mortgage Obligations
Recurring Assets, Fair Value Disclosure	17,384
Fair Value, Inputs, Level 2 | US States and Political Subdivisions Debt Securities
Recurring Assets, Fair Value Disclosure	52,342	56,646
Fair Value, Inputs, Level 2 | Interest rate derivative asset
Recurring Assets, Fair Value Disclosure	1,453	981
Fair Value, Inputs, Level 2 | Interest rate derivative liability
Recurring Assets, Fair Value Disclosure	(1,448)	(1,030)
Fair Value, Inputs, Level 3 | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises
Recurring Assets, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 3 | Collateralized Mortgage Obligations
Recurring Assets, Fair Value Disclosure	0
Fair Value, Inputs, Level 3 | US States and Political Subdivisions Debt Securities
Recurring Assets, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 3 | Interest rate derivative asset
Recurring Assets, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 3 | Interest rate derivative liability
Recurring Assets, Fair Value Disclosure	$ 0	$ 0