Consolidated Statements of Comprehensive Income (Loss) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Income Statement [Abstract]
Operating Revenue	$ 274,754	$ 306,169	$ 545,074	$ 637,085
Operating Expenses
Salaries, wages, and benefits	110,116	120,311	222,813	243,643
Rent and purchased transportation	21,688	28,468	45,551	61,611
Fuel	47,011	49,867	94,332	107,396
Operations and maintenance	16,732	16,047	32,996	31,073
Operating taxes and licenses	5,255	5,457	10,570	11,001
Insurance and claims	12,972	10,433	27,556	21,435
Communications and utilities	2,270	2,679	4,710	5,555
Depreciation and amortization	46,138	48,337	92,642	96,806
Other operating expenses	13,431	16,362	29,058	34,253
Loss (gain) on disposal of property and equipment	(1,123)	(8,022)	(1,034)	(14,809)
Total operating expenses	274,490	289,939	559,194	597,964
Operating income (loss)	264	16,230	(14,120)	39,121
Interest income	288	592	654	1,076
Interest Expense	(4,574)	(6,111)	(9,875)	(12,187)
(Loss) income before income taxes	(4,022)	10,711	(23,341)	28,010
Federal and state income taxes	(544)	2,940	(4,755)	7,627
Net (loss) income	(3,478)	7,771	(18,586)	20,383
Other comprehensive income, net of tax	0	0	0	0
Comprehensive (loss) income	$ (3,478)	$ 7,771	$ (18,586)	$ 20,383
Net (loss) income per share
Basic	$ (0.04)	$ 0.10	$ (0.24)	$ 0.26
Diluted	$ (0.04)	$ 0.10	$ (0.24)	$ 0.26
Weighted average shares outstanding
Basic	78,913	78,999	78,979	78,993
Diluted	78,981	79,081	79,051	79,052
Dividends declared per share	$ 0.02	$ 0.02	$ 0.04	$ 0.04