SEGMENTS - Reportable Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Net sales
Net sales	$ 596,100	$ 632,828	$ 686,620	$ 620,952	$ 657,449	$ 655,150	$ 642,769	$ 546,761	$ 479,277	$ 482,566	$ 449,422	$ 392,003	$ 2,536,500	$ 2,502,129	$ 1,803,268
Depreciation and amortization													45,320	46,969	48,842
Income (loss) from operations													311,949	166,642	33,542
Transportation Solutions
Net sales
Net sales													2,320,274	2,312,637	1,628,694
Parts & Services
Net sales
Net sales													216,226	189,492	174,574
Operating Segments | Transportation Solutions
Net sales
Net sales													2,338,604	2,320,914	1,633,319
Depreciation and amortization													40,443	41,187	41,819
Income (loss) from operations													366,928	209,942	61,869
Operating Segments | Parts & Services
Net sales
Net sales													220,873	193,476	177,166
Depreciation and amortization													2,201	2,717	4,781
Income (loss) from operations													44,649	30,558	20,201
Corporate and Eliminations
Net sales
Net sales													(22,977)	(12,261)	(7,217)
Depreciation and amortization													2,676	3,065	2,242
Income (loss) from operations													(99,628)	(73,858)	(48,528)
Corporate and Eliminations | Transportation Solutions
Net sales
Net sales													18,330	8,277	4,625
Corporate and Eliminations | Parts & Services
Net sales
Net sales													$ 4,647	$ 3,984	$ 2,592