Segment Information (Summary Of Segment Information) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting Information [Line Items]
Revenues	$ 702,891	$ 590,214	$ 1,969,151	$ 1,751,876
Operating Income	71,324	62,103	210,658	145,987
Truckload Transportation Services
Segment Reporting Information [Line Items]
Revenues	527,697	458,256	1,481,846	1,368,172
Operating Income	62,856	63,080	193,592	143,394
Werner Logistics
Segment Reporting Information [Line Items]
Revenues	157,968	117,351	437,494	339,678
Operating Income	7,650	(852)	16,151	3,372
Other
Segment Reporting Information [Line Items]
Revenues	17,004	14,156	49,128	42,539
Operating Income	1,406	566	3,935	2,932
Corporate
Segment Reporting Information [Line Items]
Revenues	434	481	1,222	1,542
Operating Income	(588)	(691)	(3,020)	(3,711)
Subtotal
Segment Reporting Information [Line Items]
Revenues	703,103	590,244	1,969,690	1,751,931
Inter-segment eliminations
Segment Reporting Information [Line Items]
Revenues	$ (212)	$ (30)	$ (539)	$ (55)