EMPLOYEE BENEFIT PLANS - Changes in Plan Assets, Benefit Obligations, and Funded Status (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Change in plan assets:
Other adjustments	$ (15,803)	$ (20,215)	$ (14,476)
Pension Benefits
Change in projected benefit obligation:
Beginning of year	710,769	685,254
Service cost	23,421	22,159	34,847
Interest cost	36,244	34,190	25,596
Actuarial (gain) loss	(54,744)	(8,532)
Benefits paid, net of retiree premiums	(23,599)	(22,302)
End of year	692,091	710,769	685,254
Change in plan assets:
Fair value of plan assets at beginning of year	716,273	637,330
Actual return on plan assets	53,687	95,280
Employer contributions	3,686	5,965
Retiree contributions and Medicare part D subsidies	0	0
Benefits paid	(23,599)	(22,302)
Other adjustments	0	0
Fair value of plan assets at end of year	750,047	716,273	637,330
Reconciliation of funded status
Funded status	57,956	5,504
Unrecognized actuarial gain	(123,431)	(66,073)
Unrecognized prior service cost	2,154	2,680
Net amount recognized	(63,321)	(57,889)
Short-term portion of the pension benefits	3,100	2,800
Other Benefits
Change in projected benefit obligation:
Beginning of year	134,733	101,752
Service cost	6,048	4,489	6,830
Interest cost	6,900	5,219	4,009
Actuarial (gain) loss	(17,131)	27,208
Benefits paid, net of retiree premiums	(2,281)	(3,935)
End of year	128,269	134,733	101,752
Change in plan assets:
Fair value of plan assets at beginning of year	163,367	144,686
Actual return on plan assets	13,269	22,133
Employer contributions	0	189
Retiree contributions and Medicare part D subsidies	2,446	2,449
Benefits paid	(4,906)	(6,557)
Other adjustments	178	467
Fair value of plan assets at end of year	174,354	163,367	$ 144,686
Reconciliation of funded status
Funded status	46,085	28,634
Unrecognized actuarial gain	(44,685)	(26,764)
Unrecognized prior service cost	1,273	1,428
Net amount recognized	$ 2,673	$ 3,298