PREMISES AND EQUIPMENT - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Depreciation	$ 3,127,000	$ 3,122,000	$ 3,127,000
Depreciation expense on leased assets	607,000	607,000	607,000
Gladstone Property [Member]
Depreciation	$ 141,000	$ 141,000	$ 141,000