Segment Information (Summary Of Segment Information) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Revenues	$ 2,734,372	$ 2,372,178	$ 2,463,701
Operating income	309,146	227,438	225,472
Depreciation and amortization	267,700	263,286	249,527
Truckload Transportation Services
Segment Reporting Information [Line Items]
Revenues	2,045,073	1,843,209	1,909,776
Operating income	281,823	222,007	202,660
Depreciation and amortization	245,169	239,858	228,768
Werner Logistics
Segment Reporting Information [Line Items]
Revenues	622,461	469,791	489,729
Operating income	27,873	6,005	16,288
Depreciation and amortization	8,833	7,712	7,182
Other
Segment Reporting Information [Line Items]
Revenues	66,108	57,276	61,850
Operating income	4,947	3,839	5,535
Depreciation and amortization	10,786	11,705	10,980
Corporate
Segment Reporting Information [Line Items]
Revenues	1,629	2,009	2,589
Operating income	(5,497)	(4,413)	989
Depreciation and amortization	2,912	4,011	2,597
Subtotal
Segment Reporting Information [Line Items]
Revenues	2,735,271	2,372,285	2,463,944
Inter-segment eliminations
Segment Reporting Information [Line Items]
Revenues	$ (899)	$ (107)	$ (243)