OPERATING SEGMENT DATA - Operating Expenses by Category (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
OPERATING EXPENSES
Salaries, wages, and benefits	$ 439,523	$ 436,982
Rents, purchased transportation, and other costs of services	375,319	429,605
Fuel, supplies, and expenses	109,522	122,175
Depreciation and amortization	36,833	35,010
Contingent consideration	7,320	15,040
Other	45,467	46,123
Total consolidated operating expenses	$ 1,013,984	$ 1,084,935