PENSION PLANS AND OTHER POST-RETIREMENT BENEFITS - Plan Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Post-retirement benefit obligation
Unfunded commitments	$ 0
Minimum
Post-retirement benefit obligation
Long-term investment horizon	5 years
Minimum | Equity Securities
Post-retirement benefit obligation
Target allocation (as a percent)	70.00%
Maximum
Post-retirement benefit obligation
Redemption notice period	180 days
Long-term investment horizon	15 years
Maximum | Equity Securities
Post-retirement benefit obligation
Target allocation (as a percent)	90.00%
Defined Benefit Plans
Post-retirement benefit obligation
Net plan assets	$ 617,540	$ 623,826	$ 556,967
Expected contribution in the next fiscal year	20,500
Benefit payments expected to be paid
2022	31,143
2023	32,136
2024	33,515
2025	34,550
2026	35,610
2027-2031	189,363
Defined Benefit Plans | Fair Value Level 1 and Level 2
Post-retirement benefit obligation
Total plan assets	484	16
Defined Benefit Plans | Quoted Prices In Active Markets for Identical Assets (Level 1)
Post-retirement benefit obligation
Total plan assets	484	16
Defined Benefit Plans | Cash and Cash Equivalents [Member]
Post-retirement benefit obligation
Total plan assets	459
Defined Benefit Plans | Cash and Cash Equivalents [Member] | Quoted Prices In Active Markets for Identical Assets (Level 1)
Post-retirement benefit obligation
Total plan assets	459
Defined Benefit Plans | U.S. common stocks | Fair Value Level 1 and Level 2
Post-retirement benefit obligation
Total plan assets	24	15
Defined Benefit Plans | U.S. common stocks | Quoted Prices In Active Markets for Identical Assets (Level 1)
Post-retirement benefit obligation
Total plan assets	24	15
Defined Benefit Plans | International stocks | Fair Value Level 1 and Level 2
Post-retirement benefit obligation
Total plan assets	1	1
Defined Benefit Plans | International stocks | Quoted Prices In Active Markets for Identical Assets (Level 1)
Post-retirement benefit obligation
Total plan assets	1	1
Defined Benefit Plans | Global | Fair Value Measured at Net Asset Value Per Share
Post-retirement benefit obligation
Total plan assets	223,101	232,933
Defined Benefit Plans | Real Estate | Fair Value Measured at Net Asset Value Per Share
Post-retirement benefit obligation
Total plan assets	126,980	89,508
Defined Benefit Plans | Fixed Income | Fair Value Measured at Net Asset Value Per Share
Post-retirement benefit obligation
Total plan assets	194,189	247,479
Other assets/(liabilities)		9
Defined Benefit Plans | Hedge Funds | Fair Value Measured at Net Asset Value Per Share
Post-retirement benefit obligation
Total plan assets	66,309	46,402
Defined Benefit Plans | Short-term investments | Fair Value Measured at Net Asset Value Per Share
Post-retirement benefit obligation
Total plan assets	6,477	7,479
Post-retirement Benefit Obligations
Post-retirement benefit obligation
Net plan assets	3,546	3,337	$ 3,164
Expected contribution in the next fiscal year	8,200
Benefit payments expected to be paid
2022	8,155
2023	7,710
2024	7,206
2025	6,691
2026	6,284
2027-2031	27,262
Post-retirement Benefit Obligations | Fair Value Measured at Net Asset Value Per Share
Post-retirement benefit obligation
Total plan assets	3,682	3,451
Benefit payments payable	(136)	(114)
Net plan assets	3,546	3,337
Post-retirement Benefit Obligations | Cash and Cash Equivalents [Member]
Post-retirement benefit obligation
Total plan assets	3
Post-retirement Benefit Obligations | Cash and Cash Equivalents [Member] | Quoted Prices In Active Markets for Identical Assets (Level 1)
Post-retirement benefit obligation
Total plan assets	3
Post-retirement Benefit Obligations | Global | Fair Value Measured at Net Asset Value Per Share
Post-retirement benefit obligation
Total plan assets	1,330	1,288
Post-retirement Benefit Obligations | Real Estate | Fair Value Measured at Net Asset Value Per Share
Post-retirement benefit obligation
Total plan assets	757	496
Post-retirement Benefit Obligations | Fixed Income | Fair Value Measured at Net Asset Value Per Share
Post-retirement benefit obligation
Total plan assets	1,158	1,369
Post-retirement Benefit Obligations | Hedge Funds | Fair Value Measured at Net Asset Value Per Share
Post-retirement benefit obligation
Total plan assets	395	257
Post-retirement Benefit Obligations | Short-term investments | Fair Value Measured at Net Asset Value Per Share
Post-retirement benefit obligation
Total plan assets	$ 39	$ 41