ACCUMULATED OTHER COMPREHENSIVE INCOME/(LOSS) (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
AOCI Attributable to Parent [Roll Forward]
OCI Before Reclassifications					$ (3,800)	$ (2,900)
Amounts Reclassified from AOCI					3,200	5,000
Net OCI	$ (1,293)	$ 704	$ 881	$ 1,188	(589)	2,069
Accumulated Other Comprehensive Loss
AOCI Attributable to Parent [Roll Forward]
Beginning balance		(42,300)		(76,400)	(42,300)	(76,400)
Net OCI	(1,293)	704	881	1,188
Ending balance	(42,900)		(74,300)		(42,900)	(74,300)
Qualified Cash Flow Hedging Instruments
AOCI Attributable to Parent [Roll Forward]
Beginning balance		(400)		(1,400)	(400)	(1,400)
OCI Before Reclassifications					0	0
Amounts Reclassified from AOCI					0	900
Net OCI					0	900
Ending balance	(400)		(500)		(400)	(500)
Unrealized Gains/(Losses) on Marketable Securities
AOCI Attributable to Parent [Roll Forward]
Beginning balance		400		1,100	400	1,100
OCI Before Reclassifications					(1,300)	(500)
Amounts Reclassified from AOCI					0	0
Net OCI					(1,300)	(500)
Ending balance	(900)		600		(900)	600
Defined Benefit Plans
AOCI Attributable to Parent [Roll Forward]
Beginning balance		$ (42,300)		$ (76,100)	(42,300)	(76,100)
OCI Before Reclassifications					(2,500)	(2,400)
Amounts Reclassified from AOCI					3,200	4,100
Net OCI					700	1,700
Ending balance	$ (41,600)		$ (74,400)		$ (41,600)	$ (74,400)