EMPLOYEE BENEFITS - Amounts in Accumulated Other Comprehensive Income (Loss) Recognized in Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Retirement plan curtailment expense	$ 163	$ 163	$ 0	$ 0
Recognition of loss due to settlement		(215)	0	0
Defined Benefit Pension Plan
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Net loss		2,474	1,827	1,512
Prior service (credit) cost		(14)	(14)	(14)
Retirement plan curtailment expense		151	0	0
Recognition of loss due to settlement		0	0	0
Total amount in other comprehensive income recognized in net periodic benefit cost, before tax		2,611	1,813
Deferred tax expense		(548)	(381)
Accumulated other comprehensive income (loss), net of tax		2,063	1,432
Defined Benefit Pension Plan Acquired
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Net loss		10	0	0
Prior service (credit) cost		0	0	0
Retirement plan curtailment expense		0	0	0
Recognition of loss due to settlement		215	0	0
Total amount in other comprehensive income recognized in net periodic benefit cost, before tax		225	0
Deferred tax expense		(47)	0
Accumulated other comprehensive income (loss), net of tax		178	0
Restoration Plan
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Net loss		551	559	677
Prior service (credit) cost		7	6	7
Retirement plan curtailment expense		12	0	0
Recognition of loss due to settlement		0	0	$ 0
Total amount in other comprehensive income recognized in net periodic benefit cost, before tax		570	565
Deferred tax expense		(120)	(118)
Accumulated other comprehensive income (loss), net of tax		$ 450	$ 447