INCOME TAXES - Additional Information (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
INCOME TAXES
Income tax expense	$ 5,431,000	$ 5,119,000	$ 5,409,000	$ 4,379,000	$ 5,480,000	$ 4,679,000	$ 5,110,000	$ 3,264,000	$ 20,338,000	$ 18,533,000	$ 32,304,000
Statutory percentage rate of provision									21.00%	21.00%	35.00%
Deferred Tax Assets Unrealized Gain Losses On Available for Sale Securities Gross	(3,600,000)				1,300,000				$ (3,600,000)	$ 1,300,000
Deferred Tax Liabilities Allocated To Benefit Plan	$ 512,000				$ 462,000				512,000	462,000
Non-cash, Non-operating and Non-recurring Income Tax Provision											$ 4,100,000
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount									$ 0	$ (408,000)	$ 4,137,000