Note 27: Condensed Parent Company Statements: Condensed Cash Flow Statement -- Great Southern Bancorp, Inc. (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Prepaid expenses and other assets	$ 3,002	$ (5,227)	$ 12,655
Net cash provided by operating activities	94,195	62,817	80,639
Proceeds from sale of available-for-sale securities	502	0	55,000
Net cash provided by (used in) investing activities	(381,323)	81,379	(198,730)
Proceeds from Issuance of Subordinated Notes	0	0	73,472
Net cash provided by (used in) financing activities	247,617	(181,712)	198,677
Parent Company
Operating Activity Net Income Parent Company	67,109	51,564	45,342
Increase (Decrease) Equity in Undistributed Earnings of Subsidiaries	(38,748)	(38,684)	(34,067)
Compensation expense for stock option grants	737	564	483
Net realized gains on sales of available-for-sale securities	0	0	(2,735)
Amortization of interest rate derivative	154	441	289
Prepaid expenses and other assets	13	132	175
Accounts Payable and Other Accrued Liabilities	182	(115)	1,495
Income taxes parent	(278)	6	(206)
Net cash provided by operating activities	29,169	13,908	10,776
Proceeds from sale of available-for-sale securities	0	0	3,583
Investment in Subsidiary	0	0	(60,000)
Investment/Return of principal - other investments	0	0	(2)
Net cash provided by (used in) investing activities	0	0	(56,419)
Proceeds from Issuance of Subordinated Notes	0	0	73,472
Payments for Repurchase of Warrants	(903)	0	0
Dividends, Paid-in-kind	(15,819)	(12,894)	(12,232)
Stock options excercised	2,224	3,247	2,110
Net cash provided by (used in) financing activities	(14,498)	(9,647)	63,350
Cash, Period Increase (Decrease)	14,671	4,261	17,707
Cash beginning of period	41,977	37,716	20,009
Cash end of period	56,648	41,977	37,716
Interest Paid, Including Capitalized Interest, Operating and Investing Activities	$ 5,001	$ 5,059	$ 846