CONSOLIDATED STATEMENTS OF INCOME (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Income Statement [Abstract]
Operating revenues	$ 811,096	$ 836,276	$ 1,643,810	$ 1,600,881
Operating expenses:
Salaries, wages and benefits	266,373	253,639	534,688	495,635
Fuel	77,740	125,446	169,154	213,867
Supplies and maintenance	64,964	62,656	133,189	119,681
Taxes and licenses	25,408	23,791	50,833	47,624
Insurance and claims	36,806	41,071	73,291	68,563
Depreciation and amortization	74,898	68,471	149,211	135,700
Rent and purchased transportation	217,086	197,116	437,310	382,353
Communications and utilities	4,669	3,781	9,402	7,707
Other	(4,046)	(14,618)	(13,852)	(28,683)
Total operating expenses	763,898	761,353	1,543,226	1,442,447
Operating income	47,198	74,923	100,584	158,434
Other expense (income):
Interest expense	8,139	1,787	16,055	3,226
Interest income	(1,899)	(313)	(3,451)	(588)
Loss (gain) on investments in equity securities, net	(79)	(24,095)	2	(14,289)
Loss from equity method investment	844	0	844	0
Other	86	126	93	199
Total other expense (income)	7,091	(22,495)	13,543	(11,452)
Income before income taxes	40,107	97,418	87,041	169,886
Income tax expense	10,087	23,809	21,487	41,242
Net income	30,020	73,609	65,554	128,644
Net income attributable to noncontrolling interest	(139)	(1,319)	(449)	(2,605)
Net income attributable to Werner	$ 29,881	$ 72,290	$ 65,105	$ 126,039
Earnings per share:
Basic earnings per share (in dollars per share)	$ 0.47	$ 1.12	$ 1.03	$ 1.94
Diluted earnings per share (in dollars per share)	$ 0.47	$ 1.12	$ 1.02	$ 1.93
Weighted-average common shares outstanding:
Weighted average common shares outstanding (in shares)	63,384	64,394	63,345	64,965
Shares used in computing diluted earnings per share (in shares)	63,687	64,726	63,689	65,327