GOODWILL AND INTANGIBLE ASSETS - Goodwill by Segment (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021
Increase (Decrease) in Goodwill [Roll Forward]
Beginning balance	$ 74,618	$ 0
Purchase accounting adjustments	(214)	(6,626)
Ending balance	132,717	74,618
NEHDS
Increase (Decrease) in Goodwill [Roll Forward]
Goodwill recorded in acquisition		36,534
ECM
Increase (Decrease) in Goodwill [Roll Forward]
Goodwill recorded in acquisition		44,710
ReedTMS
Increase (Decrease) in Goodwill [Roll Forward]
Goodwill recorded in acquisition	52,841
Ending balance	52,841
Baylor
Increase (Decrease) in Goodwill [Roll Forward]
Goodwill recorded in acquisition	5,472
Ending balance	5,472
TTS
Increase (Decrease) in Goodwill [Roll Forward]
Beginning balance	38,084	0
Purchase accounting adjustments	0	(6,626)
Ending balance	53,897	38,084
TTS \| NEHDS
Increase (Decrease) in Goodwill [Roll Forward]
Goodwill recorded in acquisition		0
TTS \| ECM
Increase (Decrease) in Goodwill [Roll Forward]
Goodwill recorded in acquisition		44,710
TTS \| ReedTMS
Increase (Decrease) in Goodwill [Roll Forward]
Goodwill recorded in acquisition	10,341
TTS \| Baylor
Increase (Decrease) in Goodwill [Roll Forward]
Goodwill recorded in acquisition	5,472
Werner Logistics
Increase (Decrease) in Goodwill [Roll Forward]
Beginning balance	36,534	0
Purchase accounting adjustments	(214)	0
Ending balance	78,820	36,534
Werner Logistics \| NEHDS
Increase (Decrease) in Goodwill [Roll Forward]
Goodwill recorded in acquisition		36,534
Werner Logistics \| ECM
Increase (Decrease) in Goodwill [Roll Forward]
Goodwill recorded in acquisition		$ 0
Werner Logistics \| ReedTMS
Increase (Decrease) in Goodwill [Roll Forward]
Goodwill recorded in acquisition	42,500
Werner Logistics \| Baylor
Increase (Decrease) in Goodwill [Roll Forward]
Goodwill recorded in acquisition	$ 0

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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