Segment Information (Summary Of Segment Information) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Revenues	$ 590,214	$ 618,264	$ 1,751,876	$ 1,841,914
Operating Income	62,103	53,357	145,987	159,818
Truckload Transportation Services
Segment Reporting Information [Line Items]
Revenues	458,256	480,351	1,368,172	1,423,201
Operating Income	63,080	48,870	143,394	143,488
Werner Logistics
Segment Reporting Information [Line Items]
Revenues	117,351	121,331	339,678	369,584
Operating Income	(852)	3,028	3,372	12,921
Other
Segment Reporting Information [Line Items]
Revenues	14,156	15,896	42,539	47,464
Operating Income	566	1,709	2,932	5,181
Corporate
Segment Reporting Information [Line Items]
Revenues	481	687	1,542	1,905
Operating Income	(691)	(250)	(3,711)	(1,772)
Subtotal
Segment Reporting Information [Line Items]
Revenues	590,244	618,265	1,751,931	1,842,154
Inter-segment eliminations
Segment Reporting Information [Line Items]
Revenues	$ (30)	$ (1)	$ (55)	$ (240)