BASIS OF PRESENTATION, NATURE OF OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING AND REPORTING POLICIES - Goodwill and Other Intangible Assets and Stock Based Compensation (Details)	12 Months Ended
	Dec. 31, 2020
Core deposits | Maximum
Goodwill and Other Intangible Assets and Stock-Based compensations
Amortization period of intangible assets (in years)	10 years
Core deposits | Minimum
Goodwill and Other Intangible Assets and Stock-Based compensations
Amortization period of intangible assets (in years)	7 years
Customer relationships
Goodwill and Other Intangible Assets and Stock-Based compensations
Amortization period of intangible assets (in years)	15 years