ACCOUNTING STANDARDS RECENTLY ISSUED OR ADOPTED (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Mar. 31, 2020	Jan. 01, 2020	Dec. 31, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Held-to-maturity debt securities, allowance for credit loss	$ 102	$ 102	$ 0	$ 0
Loans, allowance for credit loss			100,559
Liabilities, allowance for credit loss			2,716
U.S. Government and agency obligations
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Held-to-maturity debt securities, allowance for credit loss	0	0	0	0
Municipal bonds
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Held-to-maturity debt securities, allowance for credit loss	60	61	0	0
Corporate bonds
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Held-to-maturity debt securities, allowance for credit loss	42	41	0	0
Mortgage-backed or related securities
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Held-to-maturity debt securities, allowance for credit loss	$ 0	$ 0	0	0
Impact of Topic 326 Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Held-to-maturity debt securities, allowance for credit loss			63	63
Loans, allowance for credit loss			7,812
Liabilities, allowance for credit loss			7,022
Allowance for credit loss			14,897
Impact of Topic 326 Adoption | U.S. Government and agency obligations
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Held-to-maturity debt securities, allowance for credit loss			0	0
Impact of Topic 326 Adoption | Municipal bonds
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Held-to-maturity debt securities, allowance for credit loss			28	28
Impact of Topic 326 Adoption | Corporate bonds
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Held-to-maturity debt securities, allowance for credit loss			35	35
Impact of Topic 326 Adoption | Mortgage-backed or related securities
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Held-to-maturity debt securities, allowance for credit loss			0	$ 0
January 1, 2020 As Reported Under Topic 326
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Held-to-maturity debt securities, allowance for credit loss			63
Loans, allowance for credit loss			108,371
Liabilities, allowance for credit loss			9,738
January 1, 2020 As Reported Under Topic 326 | U.S. Government and agency obligations
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Held-to-maturity debt securities, allowance for credit loss			0
January 1, 2020 As Reported Under Topic 326 | Municipal bonds
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Held-to-maturity debt securities, allowance for credit loss			28
January 1, 2020 As Reported Under Topic 326 | Corporate bonds
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Held-to-maturity debt securities, allowance for credit loss			35
January 1, 2020 As Reported Under Topic 326 | Mortgage-backed or related securities
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Held-to-maturity debt securities, allowance for credit loss			0
Commercial real estate
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans, allowance for credit loss			30,591
Commercial real estate | Impact of Topic 326 Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans, allowance for credit loss			(2,864)
Commercial real estate | January 1, 2020 As Reported Under Topic 326
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans, allowance for credit loss			27,727
Multifamily real estate
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans, allowance for credit loss			4,754
Multifamily real estate | Impact of Topic 326 Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans, allowance for credit loss			(2,204)
Multifamily real estate | January 1, 2020 As Reported Under Topic 326
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans, allowance for credit loss			2,550
Construction and land
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans, allowance for credit loss			22,994
Construction and land | Impact of Topic 326 Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans, allowance for credit loss			2,515
Construction and land | January 1, 2020 As Reported Under Topic 326
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans, allowance for credit loss			25,509
Commercial business
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans, allowance for credit loss			23,370
Commercial business | Impact of Topic 326 Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans, allowance for credit loss			3,010
Commercial business | January 1, 2020 As Reported Under Topic 326
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans, allowance for credit loss			26,380
Agricultural business
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans, allowance for credit loss			4,120
Agricultural business | Impact of Topic 326 Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans, allowance for credit loss			(351)
Agricultural business | January 1, 2020 As Reported Under Topic 326
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans, allowance for credit loss			3,769
One-to four-family residential
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans, allowance for credit loss			4,136
One-to four-family residential | Impact of Topic 326 Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans, allowance for credit loss			7,125
One-to four-family residential | January 1, 2020 As Reported Under Topic 326
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans, allowance for credit loss			11,261
Consumer
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans, allowance for credit loss			8,202
Consumer | Impact of Topic 326 Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans, allowance for credit loss			2,973
Consumer | January 1, 2020 As Reported Under Topic 326
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans, allowance for credit loss			11,175
Unallocated
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans, allowance for credit loss			2,392
Unallocated | Impact of Topic 326 Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans, allowance for credit loss			(2,392)
Unallocated | January 1, 2020 As Reported Under Topic 326
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Loans, allowance for credit loss			0
Retained Earnings [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New credit standard (Topic 326) - impact in year of adoption			$ (11,200)