SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule Of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Accounting Policies [Abstract]
Net income attributable to Werner	$ 112,382	$ 241,256	$ 259,052
Weighted average common shares outstanding (in shares)	63,374	64,125	67,434
Dilutive effect of stock-based awards (in shares)	344	454	421
Shares used in computing diluted earnings per share (in shares)	63,718	64,579	67,855
Basic earnings per share (in dollars per share)	$ 1.77	$ 3.76	$ 3.84
Diluted earnings per share (in dollars per share)	$ 1.76	$ 3.74	$ 3.82