Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2015	Mar. 01, 2016	Jun. 30, 2015
Document and Entity Information:
Entity Registrant Name	Great Southern Bancorp Inc
Document Type	10-K
Document Period End Date	Dec. 31, 2015
Trading Symbol	gsbc
Amendment Flag	false
Entity Central Index Key	0000854560
Current Fiscal Year End Date	--12-31
Entity Common Stock, Shares Outstanding		13,891,443
Entity Public Float			$ 442,360,141
Entity Filer Category	Accelerated Filer
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	No
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	FY