DERIVATIVES - Net Gains (Losses) Relating to the Cash Flow Derivative Instruments (Details) - Derivative designated as a cash flow hedge - Interest rate swaps - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Net gains (losses) recorded in accumulated other comprehensive income and the Consolidated Statements of Income
Interest rate contracts, Amount of (loss) gain recognized in OCI included component	$ (10,455)	$ (3,601)	$ 2,493
Interest rate contracts, Amount of gain (loss) reclassified from Accumulated OCI into income included component	$ (5,016)	$ 1,588	$ 1,068