OPERATING SEGMENT DATA - Operating Expenses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
OPERATING EXPENSES
Salaries, wages, and benefits	$ 431,888	$ 439,523
Fuel, supplies, and expenses	105,946	109,522
Depreciation and amortization	39,964	36,833
Contingent consideration		7,320
Loss on sale of property and equipment	(49)	217
Other	48,879	45,467
Total consolidated operating expenses	960,447	1,013,984
Operating Segments | Asset-Based
OPERATING EXPENSES
Salaries, wages, and benefits	344,141	344,999
Fuel, supplies, and expenses	77,642	81,044
Operating taxes and licenses	13,112	13,529
Insurance	17,963	14,482
Communications and utilities	5,810	4,799
Depreciation and amortization	30,590	27,007
Rents and purchased transportation	67,161	65,671
Shared services	62,443	64,914
Loss on sale of property and equipment	23	149
Other	992	1,417
Total consolidated operating expenses	619,877	618,011
Operating Segments | Asset-Light
OPERATING EXPENSES
Purchased transportation	304,614	344,122
Salaries, wages, and benefits	25,549	30,304
Supplies and expenses	1,739	2,809
Depreciation and amortization	4,618	5,078
Shared services	17,981	16,274
Contingent consideration		7,320
Other	5,891	5,714
Total consolidated operating expenses	360,392	411,621
Other and eliminations
OPERATING EXPENSES
Total consolidated operating expenses	$ (19,822)	$ (15,648)