INCOME TAXES - SUMMARY (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Current:
Federal	$ 44.0	$ 171.5	$ 181.2
State	9.2	18.3	35.6
Foreign	3.0	1.3	2.5
Total	56.2	191.1	219.3
Deferred:
Federal	18.2	71.1	26.4
State		24.3	0.4
Foreign	1.5	1.9	(2.2)
Total deferred tax expense	19.7	97.3	24.6
Total income taxes	$ 75.9	$ 288.4	$ 243.9
Difference of Income tax expense from amounts computed by applying the statutory federal rate to income from continuing operations before income taxes
Computed federal income tax expense (as a percent)	21.00%	21.00%	21.00%
State income tax (as a percent)	2.60%	2.80%	3.10%
Foreign-derived intangible income (FDII) (as a percent)	(2.00%)	(2.40%)	(2.50%)
Valuation allowance (as a percent)			(0.30%)
Foreign taxes (as a percent)	0.40%	0.10%	0.20%
Share-based payments (as a percent)	0.50%		(0.20%)
Return to provision true-ups (as a percent)	(2.80%)	0.10%	(0.20%)
Other-net (as a percent)	0.60%	(0.30%)	(0.30%)
Effective income tax rate , Percent, Total	20.30%	21.30%	20.80%
Valuation allowances	$ 5.3	$ 7.4
Deferred tax assets:
Operating lease liabilities	77.4	102.9
Multi-employer withdrawal liabilities	12.8	13.3
Deferred compensation	11.8	10.9
U.S. State alternative minimum tax credits	7.4	8.8
Insurance reserves	6.3	7.3
Other	12.9	15.4
Total deferred tax assets	128.6	158.6
Valuation allowance	(5.3)	(7.4)
Total Deferred tax assets, net of valuation allowance	123.3	151.2
Deferred tax liabilities:
Basis differences for property and equipment	451.4	433.1
Operating lease right of use assets	75.8	100.7
Intangibles	42.3	42.0
Capital Construction Fund	206.9	194.0
Other	16.2	27.9
Total deferred tax liabilities	792.6	797.7
Deferred tax liability, net , Total	$ 669.3	$ 646.5