Segment Information (Summary Of Segment Information) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information [Line Items]
Revenues	$ 568,959	$ 627,533	$ 1,161,662	$ 1,223,650
Operating Income	52,818	58,442	83,884	106,461
Truckload Transportation Services
Segment Reporting Information [Line Items]
Revenues	445,053	479,959	909,916	942,850
Operating Income	51,225	51,665	80,314	94,618
Werner Logistics
Segment Reporting Information [Line Items]
Revenues	110,163	130,883	222,327	248,253
Operating Income	3,139	5,182	4,224	9,893
Other
Segment Reporting Information [Line Items]
Revenues	13,315	16,096	28,383	31,568
Operating Income	(534)	2,293	2,366	3,472
Corporate
Segment Reporting Information [Line Items]
Revenues	442	629	1,061	1,218
Operating Income	(1,012)	(698)	(3,020)	(1,522)
Subtotal
Segment Reporting Information [Line Items]
Revenues	568,973	627,567	1,161,687	1,223,889
Inter-segment eliminations
Segment Reporting Information [Line Items]
Revenues	$ (14)	$ (34)	$ (25)	$ (239)