ACCUMULATED OTHER COMPREHENSIVE LOSS - Schedule of Accumulated Other Comprehensive Loss (Details) - USD ($)		3 Months Ended
		Mar. 31, 2022		Mar. 31, 2021
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
BALANCE		$ 1,099,914,000		$ 912,714,000
Other comprehensive gain (loss) before reclassification		(4,169,000)		(164,000)
Reclassification to net income	[1]	509,000		1,174,000
TOTAL OTHER COMPREHENSIVE (LOSS) INCOME		(3,660,000)		1,010,000
BALANCE		1,131,300,000		952,468,000
Unrealized gain (loss) on available-for-sale securities [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
BALANCE		(142,000)		91,000
Other comprehensive gain (loss) before reclassification		(3,935,000)		(58,000)
Reclassification to net income		0	[1]	0
TOTAL OTHER COMPREHENSIVE (LOSS) INCOME		(3,935,000)		(58,000)
BALANCE		(4,077,000)		33,000
Net unrealized gain (loss) on retirement plan [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
BALANCE	[2]	(18,019,000)		(36,075,000)
Other comprehensive gain (loss) before reclassification		0		0
Reclassification to net income	[1]	509,000		(1,174,000)	[2]
TOTAL OTHER COMPREHENSIVE (LOSS) INCOME	[2]	509,000		1,174,000
BALANCE	[2]	(17,510,000)		(34,901,000)
Change in cumulative foreign currency translation adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
BALANCE		(74,000)		(35,000)
Other comprehensive gain (loss) before reclassification		(234,000)		(106,000)
Reclassification to net income		0	[1]	0
TOTAL OTHER COMPREHENSIVE (LOSS) INCOME		(234,000)		(106,000)
BALANCE		(308,000)		(141,000)
Accumulated Other Comprehensive Loss [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
BALANCE		(18,235,000)		(36,019,000)
TOTAL OTHER COMPREHENSIVE (LOSS) INCOME		(3,660,000)		1,010,000
BALANCE		$ (21,895,000)		$ (35,009,000)

[1] The Company reclassified amortization of prior service cost and actuarial loss for its retirement plan from accumulated other comprehensive loss to net income of $509,000 and $1.2 million for the three months ended March 31, 2022 and 2021, respectively.

[2] Refer to Note 17: Supplemental Executive Retirement Plan.