Note 15: Disclosures About Fair Value of Financial Instruments: Fair Value, Assets Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises
Recurring Assets, Fair Value Disclosure	$ 153,258	$ 122,533
Collateralized Mortgage Obligations
Recurring Assets, Fair Value Disclosure	39,260
US States and Political Subdivisions Debt Securities
Recurring Assets, Fair Value Disclosure	51,450	56,646
Interest rate derivative asset
Recurring Assets, Fair Value Disclosure	12,800	981
Interest rate derivative liability
Recurring Assets, Fair Value Disclosure	(716)	(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	153,258	122,533
Fair Value, Inputs, Level 2 | Collateralized Mortgage Obligations
Recurring Assets, Fair Value Disclosure	39,260
Fair Value, Inputs, Level 2 | US States and Political Subdivisions Debt Securities
Recurring Assets, Fair Value Disclosure	51,450	56,646
Fair Value, Inputs, Level 2 | Interest rate derivative asset
Recurring Assets, Fair Value Disclosure	12,800	981
Fair Value, Inputs, Level 2 | Interest rate derivative liability
Recurring Assets, Fair Value Disclosure	(716)	(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