Segment Information (Summary Of Segment Information) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Segment Reporting Information [Line Items]
Revenues	$ 649,814	$ 568,959	$ 1,266,260	$ 1,161,662
Operating Income	76,863	52,818	139,334	83,884
Truckload Transportation Services
Segment Reporting Information [Line Items]
Revenues	491,200	445,053	954,149	909,916
Operating Income	73,108	51,225	130,736	80,314
Werner Logistics
Segment Reporting Information [Line Items]
Revenues	141,673	110,163	279,526	222,327
Operating Income	3,927	3,139	8,501	4,224
Other
Segment Reporting Information [Line Items]
Revenues	16,725	13,315	32,124	28,383
Operating Income	1,663	(534)	2,529	2,366
Corporate
Segment Reporting Information [Line Items]
Revenues	409	442	788	1,061
Operating Income	(1,835)	(1,012)	(2,432)	(3,020)
Subtotal
Segment Reporting Information [Line Items]
Revenues	650,007	568,973	1,266,587	1,161,687
Inter-segment eliminations
Segment Reporting Information [Line Items]
Revenues	$ (193)	$ (14)	$ (327)	$ (25)