OPERATING SEGMENT DATA - Operating Expenses by Category (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
OPERATING EXPENSES
Salaries, wages, and benefits	$ 1,768,581	$ 1,781,304	$ 1,728,653
Rents, purchased transportation, and other costs of services	1,478,114	1,642,669	2,100,663
Fuel, supplies, and expenses	433,237	479,688	488,009
Depreciation and amortization	149,087	145,349	138,159
Contingent consideration	(90,250)	(19,100)	18,300
Asset impairment charges	1,700	30,162
Other	194,116	194,752	160,698
Total consolidated operating expenses	3,934,585	4,254,824	4,634,482
Gain on sale of subsidiaries			402
Gain on sale of property and equipment	2,176	(4,797)	11,650
Innovative technology costs	34,100	52,400	40,800
Operating Segments | Asset-Based
OPERATING EXPENSES
Salaries, wages, and benefits	1,387,491	1,379,756	1,293,487
Fuel, supplies, and expenses	316,526	361,355	378,558
Depreciation and amortization	110,021	104,165	97,322
Asset impairment charges		700
Other	3,800	4,829	4,175
Total consolidated operating expenses	2,507,531	2,617,852	2,629,767
Gain related to sale of property and equipment and sale of replaced equipment and like-kind exchange of service center property			12,500
Operating Segments | Asset-Light
OPERATING EXPENSES
Salaries, wages, and benefits	118,983	129,083	150,694
Depreciation and amortization	20,062	20,370	20,730
Contingent consideration	(90,250)	(19,100)	18,300
Asset impairment charges	1,700	14,407
Other	25,362	25,650	31,163
Total consolidated operating expenses	1,494,492	1,692,916	2,086,547
Legal settlement	274	9,500
Gain on sale of subsidiaries			402
Other and eliminations
OPERATING EXPENSES
Depreciation and amortization	19,004	20,814	20,107
Asset impairment charges		15,100
Total consolidated operating expenses	$ (67,438)	$ (55,944)	$ (81,832)