Note 3: Loans and Allowance for Loan Losses: Impaired Financing Receivables (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Loans Receivable
Impaired Financing Receivable, Recorded Investment	$ 13,939	$ 25,334	$ 34,281
Impaired Financing Receivable, Unpaid Principal Balance	15,579	27,655	36,823
Impaired Financing Receivable, Related Allowance	2,041	3,951	6,362
Impaired Financing Receivable, Average Recorded Investment	20,004	30,193	50,012
Impaired Financing Receivable Interest Income Recognized	1,346	1,588	2,315
Land and Land Improvements
Impaired Financing Receivable, Recorded Investment	14	15	6,023
Impaired Financing Receivable, Unpaid Principal Balance	18	18	6,120
Impaired Financing Receivable, Related Allowance	0	0	1,291
Impaired Financing Receivable, Average Recorded Investment	14	1,793	8,020
Impaired Financing Receivable Interest Income Recognized	1	24	304
One- to four-family residential construction
Impaired Financing Receivable, Recorded Investment	0	0	0
Impaired Financing Receivable, Unpaid Principal Balance	0	0	0
Impaired Financing Receivable, Related Allowance	0	0	0
Impaired Financing Receivable, Average Recorded Investment	0	193	0
Impaired Financing Receivable Interest Income Recognized	0	0	0
Subdivision construction
Impaired Financing Receivable, Recorded Investment	318	349	818
Impaired Financing Receivable, Unpaid Principal Balance	318	367	829
Impaired Financing Receivable, Related Allowance	105	114	131
Impaired Financing Receivable, Average Recorded Investment	321	584	948
Impaired Financing Receivable Interest Income Recognized	17	22	46
Commercial construction
Impaired Financing Receivable, Recorded Investment	0	0	0
Impaired Financing Receivable, Unpaid Principal Balance	0	0	0
Impaired Financing Receivable, Related Allowance	0	0	0
Impaired Financing Receivable, Average Recorded Investment	0	0	0
Impaired Financing Receivable Interest Income Recognized	0	0	0
Owner occupied one- to four-family residential
Impaired Financing Receivable, Recorded Investment	3,576	3,405	3,290
Impaired Financing Receivable, Unpaid Principal Balance	3,926	3,723	3,555
Impaired Financing Receivable, Related Allowance	285	331	374
Impaired Financing Receivable, Average Recorded Investment	3,406	3,405	3,267
Impaired Financing Receivable Interest Income Recognized	197	166	182
Non-owner occupied one- to four-family residential
Impaired Financing Receivable, Recorded Investment	2,222	3,196	1,907
Impaired Financing Receivable, Unpaid Principal Balance	2,519	3,465	2,177
Impaired Financing Receivable, Related Allowance	304	68	65
Impaired Financing Receivable, Average Recorded Investment	2,870	2,419	1,886
Impaired Financing Receivable Interest Income Recognized	158	165	113
Commercial Real Estate
Impaired Financing Receivable, Recorded Investment	3,501	8,315	10,507
Impaired Financing Receivable, Unpaid Principal Balance	3,665	8,490	12,121
Impaired Financing Receivable, Related Allowance	613	599	2,209
Impaired Financing Receivable, Average Recorded Investment	6,216	9,075	23,928
Impaired Financing Receivable Interest Income Recognized	337	567	984
Other residential
Impaired Financing Receivable, Recorded Investment	0	2,907	3,812
Impaired Financing Receivable, Unpaid Principal Balance	0	2,907	3,812
Impaired Financing Receivable, Related Allowance	0	0	0
Impaired Financing Receivable, Average Recorded Investment	1,026	3,553	6,813
Impaired Financing Receivable Interest Income Recognized	20	147	258
Commercial business
Impaired Financing Receivable, Recorded Investment	1,844	3,018	4,539
Impaired Financing Receivable, Unpaid Principal Balance	2,207	4,222	4,652
Impaired Financing Receivable, Related Allowance	309	2,140	1,295
Impaired Financing Receivable, Average Recorded Investment	2,932	5,384	2,542
Impaired Financing Receivable Interest Income Recognized	362	173	185
Industrial revenue bonds
Impaired Financing Receivable, Recorded Investment	0	0	0
Impaired Financing Receivable, Unpaid Principal Balance	0	0	0
Impaired Financing Receivable, Related Allowance	0	0	0
Impaired Financing Receivable, Average Recorded Investment	0	0	0
Impaired Financing Receivable Interest Income Recognized	0	0	0
Automobile Loan
Impaired Financing Receivable, Recorded Investment	1,874	2,713	2,097
Impaired Financing Receivable, Unpaid Principal Balance	2,114	2,898	2,178
Impaired Financing Receivable, Related Allowance	336	484	629
Impaired Financing Receivable, Average Recorded Investment	2,069	2,383	1,307
Impaired Financing Receivable Interest Income Recognized	167	222	141
Consumer Loan
Impaired Financing Receivable, Recorded Investment	479	825	812
Impaired Financing Receivable, Unpaid Principal Balance	684	917	887
Impaired Financing Receivable, Related Allowance	72	124	244
Impaired Financing Receivable, Average Recorded Investment	738	906	884
Impaired Financing Receivable Interest Income Recognized	59	69	70
Home Equity Line of Credit
Impaired Financing Receivable, Recorded Investment	111	591	476
Impaired Financing Receivable, Unpaid Principal Balance	128	648	492
Impaired Financing Receivable, Related Allowance	17	91	124
Impaired Financing Receivable, Average Recorded Investment	412	498	417
Impaired Financing Receivable Interest Income Recognized	$ 28	$ 33	$ 32