OPERATING SEGMENT DATA - Operating Expenses by Category (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
OPERATING EXPENSES
Salaries, wages, and benefits	$ 455,685	$ 456,022	$ 1,348,491	$ 1,342,123
Rents, purchased transportation, and other costs of services	369,785	410,436	1,121,241	1,255,753
Fuel, supplies, and expenses	109,017	122,552	330,676	368,432
Depreciation and amortization	36,611	37,141	109,720	107,962
Contingent consideration	(91,910)	(17,840)	(80,740)	(12,800)
Lease impairment charges		30,162		30,162
Other	48,943	44,786	141,713	137,910
Total consolidated operating expenses	$ 928,131	$ 1,083,259	$ 2,971,101	$ 3,229,542