FAIR VALUE - Summary of carrying amounts and estimated fair values for financial instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Summary of carrying amounts and estimated fair values for financial instruments
Cash and cash equivalents	$ 78,638	$ 73,357	$ 9,502
Fair Value	58,903	43,695
Loans, net	990,132	886,515
Mortgage loans held for sale	48,312	14,832
Accrued interest receivable	3,048	2,844
Other assets	16,544	3,724
Deposits	1,086,784	937,758
FHLB Topeka Borrowings – fixed rate	10,000	15,000
Subordinated notes	6,560	6,560
Accrued interest payable	299	231
Carrying Amount
Summary of carrying amounts and estimated fair values for financial instruments
Cash and cash equivalents	78,638	73,357
Fair Value	58,903	43,695
Loans, net	990,132	886,515
Mortgage loans held for sale	48,312	14,832
Accrued interest receivable	3,048	2,844
Other assets	713	693
Deposits	1,086,784	937,758
FHLB Topeka Borrowings – fixed rate	10,000	15,000
Accrued interest payable	299	231
2016 Subordinated notes – fixed-to-floating rate | Carrying Amount
Summary of carrying amounts and estimated fair values for financial instruments
Subordinated notes	6,560	6,560
Level 1 | Estimated Fair Value
Summary of carrying amounts and estimated fair values for financial instruments
Cash and cash equivalents	78,638	73,357
Fair Value	254	250
Other assets	713	693
Level 2 | Estimated Fair Value
Summary of carrying amounts and estimated fair values for financial instruments
Fair Value	58,649	43,445
Mortgage loans held for sale	48,312	14,832
Accrued interest receivable	3,048	2,844
Deposits	1,089,261	940,039
FHLB Topeka Borrowings – fixed rate	10,003	14,833
Accrued interest payable	299	231
Level 3 | Estimated Fair Value
Summary of carrying amounts and estimated fair values for financial instruments
Loans, net	974,142	868,828
Level 3 | 2016 Subordinated notes – fixed-to-floating rate | Estimated Fair Value
Summary of carrying amounts and estimated fair values for financial instruments
Subordinated notes	$ 6,004	$ 6,434