PENSION AND OTHER BENEFIT PLANS - Net periodic benefit cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Prior service costs
Maximum percentage of net gain or loss over the greater of the projected benefit obligation or the market-related value of assets without requiring amortization	10.00%
Pension Benefits
Net periodic benefit cost
Service cost	$ 4,959	$ 5,920	$ 5,750
Interest cost	5,334	5,036	5,657
Expected return on plan assets	(19,025)	(18,783)	(16,306)
Plan amendment	(556)	0	(637)
Amortization of unrecognized net loss	842	3,600	3,239
Amortization of prior service cost	615	379	241
Net periodic (benefit)	(7,831)	(3,848)	2,056
Post-retirement Benefits
Net periodic benefit cost
Service cost	0	0	0
Interest cost	68	44	57
Expected return on plan assets	0	0	0
Plan amendment	0	0	0
Amortization of unrecognized net loss	23	45	40
Amortization of prior service cost	(179)	(179)	(179)
Net periodic (benefit)	$ (88)	$ (90)	$ (82)