Segment Reporting - Summarize our Financial and Operating Data by Segment (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Segment Reporting Information [Line Items]
Operating revenue	$ 986,495	$ 1,040,462	$ 1,985,988	$ 2,192,727
Operating income	39,528	62,070	76,667	140,275
Depreciation and amortization	37,772	35,386	76,103	70,835
Intermodal [Member]
Segment Reporting Information [Line Items]
Operating revenue	561,033	614,632	1,113,066	1,323,881
Operating income	13,639	31,777	26,670	80,981
Depreciation and amortization	27,270	27,117	54,319	54,003
Logistics [Member]
Segment Reporting Information [Line Items]
Operating revenue	459,088	453,549	939,312	922,690
Operating income	25,889	30,293	49,997	59,294
Depreciation and amortization	10,502	8,269	21,784	16,832
Inter-segment [Member]
Segment Reporting Information [Line Items]
Operating revenue	$ (33,626)	$ (27,719)	$ (66,390)	$ (53,844)