INCOME TAXES - Additional Information (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
INCOME TAXES
Income tax expense	$ 6,071,000	$ 5,377,000	$ 4,448,000	$ 3,643,000	$ 5,431,000	$ 5,119,000	$ 5,409,000	$ 4,379,000	$ 19,539,000	$ 20,338,000	$ 18,533,000
Statutory percentage rate of provision									21.00%	21.00%	21.00%
Deferred Tax Assets Unrealized Gain Losses On Available for Sale Securities Gross	(7,800,000)				(3,600,000)				$ (7,800,000)	$ (3,600,000)
Deferred Tax Liabilities Allocated To Benefit Plan	$ 476,000				$ 512,000				$ 476,000	$ 512,000
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount											$ (408,000)