FAIR VALUE MEASUREMENTS (Narrative) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2021 USD ($) item	Mar. 31, 2020 USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Number of Rabbi Trusts established | item	2
Net gains (losses) of the Rabbi Trust investments	$ 1,986	$ (5,060)
Unrealized net gains (losses) of the Rabbi Trusts' investments	$ 1,633	$ (5,060)