LOANS RECEIVABLE AND THE ALLOWANCE FOR LOAN LOSSES (Troubled Debt Restructuring) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Financing Receivable, Modifications [Line Items]
TDRs on Accrual Status	$ 13,793	$ 16,115
TDRs on Nonaccrual Status	327	917
Total TDRs	14,120	17,032
Commitments to advance funds related to TDRs, maximum additional amounts	23	45
Commerical real estate - owner-occupied [Member]
Financing Receivable, Modifications [Line Items]
TDRs on Accrual Status	202	199
TDRs on Nonaccrual Status	83	87
Total TDRs	285	286
Commercial real estate - investment properties [Member]
Financing Receivable, Modifications [Line Items]
TDRs on Accrual Status	5,668	6,884
TDRs on Nonaccrual Status	0	0
Total TDRs	5,668	6,884
Commercial business [Member]
Financing Receivable, Modifications [Line Items]
TDRs on Accrual Status	369	555
TDRs on Nonaccrual Status	0	0
Total TDRs	369	555
Agricultural business, including secured by farmland [Member]
Financing Receivable, Modifications [Line Items]
TDRs on Accrual Status	2,560	3,129
TDRs on Nonaccrual Status	0	29
Total TDRs	2,560	3,158
One- to four-family residential [Member]
Financing Receivable, Modifications [Line Items]
TDRs on Accrual Status	4,789	5,136
TDRs on Nonaccrual Status	244	801
Total TDRs	5,033	5,937
Consumer secured by one- to four-family [Member]
Financing Receivable, Modifications [Line Items]
TDRs on Accrual Status	136	139
TDRs on Nonaccrual Status	0	0
Total TDRs	136	139
Consumer - other [Member]
Financing Receivable, Modifications [Line Items]
TDRs on Accrual Status	69	73
TDRs on Nonaccrual Status	0	0
Total TDRs	$ 69	$ 73