Unaudited Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Operating revenue
Revenue	$ 460,227	$ 390,126	$ 1,335,693	$ 1,124,152
Operating expenses
Salaries, wages, and benefits	128,117	137,336	400,742	402,801
Fuel and fuel taxes	57,423	53,865	173,516	156,045
Vehicle rents	19,497	15,579	58,912	55,747
Depreciation and amortization, net of (gain) loss on sale of property	24,541	23,264	73,396	69,022
Operating expenses and supplies	30,538	32,185	89,402	96,724
Insurance premiums and claims	25,128	17,533	64,463	52,557
Operating taxes and licenses	3,522	3,375	10,432	9,839
Communications and utilities	2,258	1,861	7,149	5,782
General and other operating expenses	16,579	17,970	49,728	46,007
Total operating expenses	437,335	378,592	1,277,929	1,108,001
Operating income	22,892	11,534	57,764	16,151
Other expense (income)
Interest expense, net	4,815	12,941	29,771	36,365
Early extinguishment of debt			7,753
Equity in (income) loss of affiliated companies	73	160	250	1,160
Other, net	(133)	101	34	(707)
Total other expenses (income)	4,755	13,202	37,808	36,818
Income (loss) before income tax provision (benefit)	18,137	(1,668)	19,956	(20,667)
Income tax provision (benefit)	1,679	(1,008)	1,081	(7,203)
Net total and comprehensive income (loss)	16,458	(660)	18,875	(13,464)
Net total and comprehensive income attributable to noncontrolling interest	329	15	972	95
Net total and comprehensive income (loss) attributable to controlling interest	$ 16,129	$ (675)	$ 17,903	$ (13,559)
Earnings (loss) per share
Basic earnings (loss) per share (in dollars per share)	$ 0.33	$ (0.11)	$ 0.77	$ (2.12)
Basic weighted average shares outstanding (in shares)	48,296	6,385	23,118	6,385
Diluted earnings (loss) per share (in dollars per share)	$ 0.33	$ (0.11)	$ 0.76	$ (2.12)
Diluted weighted average shares outstanding (in shares)	49,597	6,385	23,638	6,385
Cargo and Freight [Member]
Operating revenue
Revenue	$ 413,887	$ 356,379	$ 1,199,553	$ 1,026,684
Fuel Surcharge [Member]
Operating revenue
Revenue	46,340	33,747	136,140	97,468
Shipping and Handling [Member]
Operating expenses
Purchased transportation	$ 129,732	$ 75,624	$ 350,189	$ 213,477