ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Summary of the Accumulated Other Comprehensive (Loss) Income Balances, Net of Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Unrealized (losses) gains on available for sale securities
Balance at the beginning of the period	$ (829)
Current Period Change	3,916	$ 10,856	$ (348)
Balance at the end of the period	(3,087)	(829)
Unrealized losses on pension benefits
Balance at the beginning of the period	(6,775)
Current Period Change	(1,865)	(410)	(832)
Balance at the end of the period	(8,640)	(6,775)
Unrealized losses on cash flow hedges
Balance at the beginning of the period	(737)
Current Period Change	(3,838)	(3,675)	1,007
Balance at the end of the period	(4,575)	(737)
Accumulated other comprehensive loss, net of income taxes
Balance at the beginning of the period	(8,341)
Current Period Change	(1,787)	6,771	$ (173)
Balance at the end of the period	$ (10,128)	$ (8,341)