Note 15: Disclosures About Fair Value of Financial Instruments: Fair Value Measurement, Policy: Fair Value, Assets Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises
Recurring Assets, Fair Value Disclosure	$ 180,196	$ 153,258
Collateralized Mortgage Obligations
Recurring Assets, Fair Value Disclosure	53,006	39,260
US States and Political Subdivisions Debt Securities
Recurring Assets, Fair Value Disclosure	44,548	51,450
Interest rate derivative asset
Recurring Assets, Fair Value Disclosure	20,338	12,800
Interest rate derivative liability
Recurring Assets, Fair Value Disclosure	(768)	(716)
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	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	180,196	153,258
Fair Value, Inputs, Level 2 | Collateralized Mortgage Obligations
Recurring Assets, Fair Value Disclosure	53,006	39,260
Fair Value, Inputs, Level 2 | US States and Political Subdivisions Debt Securities
Recurring Assets, Fair Value Disclosure	44,548	51,450
Fair Value, Inputs, Level 2 | Interest rate derivative asset
Recurring Assets, Fair Value Disclosure	20,338	12,800
Fair Value, Inputs, Level 2 | Interest rate derivative liability
Recurring Assets, Fair Value Disclosure	(768)	(716)
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	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