OPERATING SEGMENT DATA - Operating Expenses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
OPERATING EXPENSES FROM CONTINUING OPERATIONS
Salaries, wages, and benefits	$ 436,982	$ 414,905
Fuel, supplies, and expenses	122,618	110,359
Depreciation and amortization	35,010	34,396
Contingent consideration	15,040	810
Pre-tax gain on sale of discontinued operations	(69,083)
Gain on sale of property and equipment	(9)	(3,002)
Other	45,680	36,829
Total consolidated operating expenses	1,084,935	1,175,148
Operating Segments | Asset Based
OPERATING EXPENSES FROM CONTINUING OPERATIONS
Salaries, wages, and benefits	335,605	313,497
Fuel, supplies, and expenses	94,288	84,831
Operating taxes and licenses	13,979	12,493
Insurance	13,273	10,431
Communications and utilities	5,304	4,687
Depreciation and amortization	24,911	24,305
Rents and purchased transportation	90,744	102,985
Shared services	64,613	67,150
Gain on sale of property and equipment	(51)	(2,695)
Innovative technology costs	6,068	6,960
Other	1,612	633
Total consolidated operating expenses	650,346	625,277
Operating Segments | Asset-Light
OPERATING EXPENSES FROM CONTINUING OPERATIONS
Purchased transportation	370,163	508,380
Supplies and expenses	4,072	3,266
Depreciation and amortization	5,068	5,180
Shared services	51,429	50,197
Contingent consideration	15,040	810
Other	6,411	6,335
Total consolidated operating expenses	452,183	574,168
Other and eliminations
OPERATING EXPENSES FROM CONTINUING OPERATIONS
Total consolidated operating expenses	$ (17,594)	$ (24,297)