Note 18: Commitments and Credit Risk: Letters of Credit (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Letters of Credit Outstanding, Amount	$ 28,900	$ 20,000
Letters of Credit Terms Up to Five Years	28,400	19,100
Commercial Lines of Credit
Letters of Credit Outstanding, Amount	1,100,000	912,200
Open-end Consumer Lines of Credit
Letters of Credit Outstanding, Amount	$ 150,900	$ 133,600