Note 21: Stock Compensation Plans: Schedule of Fair Value Option Pricing Model Assumptions (Details) - $ / shares	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Details
Fair Value Assumptions, Expected Dividend Payments	$ 0.95	$ 0.88	$ 0.88
Fair Value Assumptions, Risk Free Interest Rate	2.03%	1.27%	1.66%
Fair Value Assumptions, Expected Term, Simplified Method	5 years	5 years	5 years
Fair Value Assumptions, Expected Volatility Rate	23.49%	22.08%	24.42%
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 10.04	$ 6.59	$ 9.59

Amount of dividends expected to be paid to holders of the underlying shares or contracted instruments over the term of the instruments life.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

+ Details

Name:	us-gaap_FairValueAssumptionsExpectedDividendPayments
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Description of the expected term under the specified contract (or assumed time period) the instrument will be outstanding before being exercised, placed into service or terminated, the reason and justification for its use, and the periods for which the method was used.

+ References

+ Details

Name:	us-gaap_FairValueAssumptionsExpectedTermSimplifiedMethod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Measure of dispersion, in percentage terms (for instance, the standard deviation or variance), for a given stock price.

+ References

+ Details

Name:	us-gaap_FairValueAssumptionsExpectedVolatilityRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Risk-free interest rate assumption used in valuing an instrument.

+ References

+ Details

Name:	us-gaap_FairValueAssumptionsRiskFreeInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (d)(1)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_TextBlockAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration