PENSION PLANS AND OTHER POSTRETIREMENT BENEFITS - Components of Net Periodic Benefit Cost (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 8,263	$ 10,685	$ 24,773	$ 32,507
Expected return on plan assets	(15,452)	(13,901)	(46,636)	(41,700)
Amortization of prior service cost	44	28	130	83
Recognized net actuarial (gain) loss	0	18	0	1,278
Benefit plans, net	(7,145)	(3,170)	(21,733)	(7,832)
Service cost included in COS	212	346	632	646
Net periodic benefit cost (benefit)	(6,933)	(2,824)	(21,101)	(7,186)
Other Benefits
Defined Benefit Plan Disclosure [Line Items]
Interest cost	88	139	232	378
Expected return on plan assets	0	0	0	0
Amortization of prior service cost	(271)	(540)	(813)	(1,618)
Recognized net actuarial (gain) loss	0	0	0	0
Benefit plans, net	(183)	(401)	(581)	(1,240)
Service cost included in COS	5	4	14	12
Net periodic benefit cost (benefit)	$ (178)	$ (397)	$ (567)	$ (1,228)