LOANS RECEIVABLE AND THE ALLOWANCE FOR LOAN LOSSES (Troubled Debt Restructuring) (Details)	9 Months Ended
	Sep. 30, 2019 USD ($) contract	Sep. 30, 2018 contract	Dec. 31, 2018 USD ($)
Financing Receivable, Troubled Debt Restructuring [Line Items]
TDRs on Accrual Status	$ 6,721,000		$ 13,422,000
TDRs on Nonaccrual Status	1,526,000		317,000
Total TDRs	8,247,000		13,739,000
Commitments to advance funds related to TDRs, maximum additional amounts	$ 27,000		0
Number of Contracts | contract	3	0
Pre-modification Outstanding Recorded Investment	$ 1,846,000
Post-modification Outstanding Recorded Investment	1,846,000
Commerical real estate - owner-occupied [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
TDRs on Accrual Status	0		200,000
TDRs on Nonaccrual Status	268,000		78,000
Total TDRs	268,000		278,000
Commercial real estate - investment properties [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
TDRs on Accrual Status	694,000		5,606,000
TDRs on Nonaccrual Status	1,059,000		0
Total TDRs	$ 1,753,000		5,606,000
Number of Contracts | contract	1
Pre-modification Outstanding Recorded Investment	$ 1,090,000
Post-modification Outstanding Recorded Investment	1,090,000
Commercial business [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
TDRs on Accrual Status	560,000		391,000
TDRs on Nonaccrual Status	0		0
Total TDRs	$ 560,000		391,000
Number of Contracts | contract	1
Pre-modification Outstanding Recorded Investment	$ 160,000
Post-modification Outstanding Recorded Investment	160,000
Agricultural business, including secured by farmland [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
TDRs on Accrual Status	2,281,000		2,561,000
TDRs on Nonaccrual Status	0		0
Total TDRs	$ 2,281,000		2,561,000
Number of Contracts | contract	1
Pre-modification Outstanding Recorded Investment	$ 596,000
Post-modification Outstanding Recorded Investment	596,000
One- to four-family residential [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
TDRs on Accrual Status	3,001,000		4,469,000
TDRs on Nonaccrual Status	199,000		239,000
Total TDRs	3,200,000		4,708,000
Consumer secured by one- to four-family [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
TDRs on Accrual Status	129,000		133,000
TDRs on Nonaccrual Status	0		0
Total TDRs	129,000		133,000
Consumer - other [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
TDRs on Accrual Status	56,000		62,000
TDRs on Nonaccrual Status	0		0
Total TDRs	$ 56,000		$ 62,000