FAIR VALUE OF FINANCIAL INSTRUMENTS - Unobservable inputs used in nonrecurring measurements (Details) - Nonrecurring - Level 3 $ in Thousands	Jun. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)
Collateral-dependent impaired loans
FAIR VALUE OF FINANCIAL INSTRUMENTS
Alternative Investment, Measurement Input [Extensible List]	hbt:AppraisalAdjustmentsMember	hbt:AppraisalAdjustmentsMember
Collateral-dependent impaired loans | Appraisal of collateral
FAIR VALUE OF FINANCIAL INSTRUMENTS
Fair Value	$ 23,926	$ 33,320
Bank premises held for sale
FAIR VALUE OF FINANCIAL INSTRUMENTS
Alternative Investment, Measurement Input [Extensible List]	hbt:AppraisalAdjustmentsMember	hbt:AppraisalAdjustmentsMember
Bank premises held for sale | Appraisal
FAIR VALUE OF FINANCIAL INSTRUMENTS
Fair Value	$ 121	$ 121
Measurement input	7	7
Bank premises held for sale | Appraisal | Weighted average
FAIR VALUE OF FINANCIAL INSTRUMENTS
Measurement input	7	7
Foreclosed assets
FAIR VALUE OF FINANCIAL INSTRUMENTS
Alternative Investment, Measurement Input [Extensible List]	hbt:AppraisalAdjustmentsMember	hbt:AppraisalAdjustmentsMember
Foreclosed assets | Appraisal
FAIR VALUE OF FINANCIAL INSTRUMENTS
Fair Value	$ 7,757	$ 4,168
Measurement input	7	7
Foreclosed assets | Appraisal | Weighted average
FAIR VALUE OF FINANCIAL INSTRUMENTS
Measurement input	7	7