Note 15: Disclosures About Fair Value of Financial Instruments: Fair Value, Assets Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises
Assets, Fair Value Disclosure, Recurring	$ 122,533	$ 146,035
US States and Political Subdivisions Debt Securities
Assets, Fair Value Disclosure, Recurring	56,646	67,837
Interest Rate Swap Asset
Assets, Fair Value Disclosure, Recurring	981	1,663
Interest Rate Swap Liability
Assets, Fair Value Disclosure, Recurring	$ (1,030)	$ (1,699)