OPERATING SEGMENT DATA - Operating Expenses by Category (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
OPERATING EXPENSES
Salaries, wages, and benefits	$ 449,024	$ 442,875	$ 886,006	$ 857,780
Rents, purchased transportation, and other costs of services	415,712	538,238	845,317	1,116,087
Fuel, supplies, and expenses	124,148	129,505	246,766	239,864
Depreciation and amortization	35,811	34,884	70,821	69,280
Contingent consideration	(10,000)		5,040	810
Other	46,653	40,152	92,333	76,981
Total consolidated operating expenses	$ 1,061,348	$ 1,185,654	$ 2,146,283	$ 2,360,802