OTHER COMPREHENSIVE INCOME : OTHER COMPREHENSIVE INCOME (LOSS)-Reclassifications (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net securities gains (losses)		$ 114	$ 233	$ 44
Income tax expense		(12,626)	(11,692)	(12,127)
NET INCOME		52,987	53,844	48,872
Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
NET INCOME		(1,469)	(1,300)	(1,135)
Unrealized Gains and Losses on Available-for-Sale Securities | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net securities gains (losses)		114	233	44
Income tax expense		(29)	(58)	(11)
NET INCOME		85	175	33
Retirement Plans | Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Change in funded status of post retirement benefits	[1]	(2,072)	(1,967)	(1,558)
Income tax expense		518	492	390
NET INCOME		$ (1,554)	$ (1,475)	$ (1,168)

[1] Included in the computation of net periodic benefit cost which is included in salaries and benefits. (see Footnote 16 for additional details).