INCOME TAXES - Effective Income Tax and the U.S. Statutory Income Tax Rate (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Effective income tax rate and the U.S. statutory income tax rate
Income tax expense at United States statutory income tax rate	$ (2.2)	$ 14.6	$ 17.2
Federal income tax effects of:
State income tax expense, net of federal benefit	1.4	1.0	6.9
Impairment of goodwill	2.8	1.2	0.0
Foreign tax rate differential	0.4	0.5	0.3
Driver per diem	1.0	0.0	0.0
Global intangible low-taxed income inclusion	0.4	0.7	0.0
Other nondeductible expenses	0.4	0.7	(0.1)
Nondeductible officer compensation	1.8	1.6	1.8
Write-off of foreign deferred tax assets	0.0	10.5	0.0
Change in valuation allowance	0.0	(10.2)	0.0
Change in fair value of warrant liability	0.0	(1.0)	(0.3)
Stock compensation	0.2	0.1	(0.5)
Tax credits	(0.2)	(0.1)	(0.1)
Return-to-provision adjustments	(0.3)	0.1	0.3
Other	1.6	(0.1)	0.5
Income tax expense (benefit)	$ 7.3	$ 19.6	$ 26.0
Effective tax rate	(70.20%)	28.10%	31.70%