Segment Reporting - Summarize our Financial and Operating Data by Segment (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Segment Reporting Information [Line Items]
Operating revenue	$ 1,040,462	$ 1,401,456	$ 2,192,727	$ 2,699,579
Operating income	62,070	137,636	140,275	252,696
Depreciation and amortization	35,386	32,244	70,835	63,533
Intermodal [Member]
Segment Reporting Information [Line Items]
Operating revenue	614,632	875,150	1,323,881	1,651,720
Operating income	31,777	100,601	80,981	186,297
Depreciation and amortization	27,117	25,383	54,003	49,758
Logistics [Member]
Segment Reporting Information [Line Items]
Operating revenue	453,549	548,613	922,690	1,089,597
Operating income	30,293	37,035	59,294	66,399
Depreciation and amortization	8,269	6,861	16,832	13,775
Inter-segment [Member}
Segment Reporting Information [Line Items]
Operating revenue	$ (27,719)	$ (22,307)	$ (53,844)	$ (41,738)