Segment Reporting - Summary of Company's Reportable Segment Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Sep. 29, 2018	Sep. 30, 2017	Dec. 31, 2017
Segment Reporting Information [Line Items]
Revenues	$ 374,292	$ 313,001	$ 1,075,330	$ 902,642
Income (loss) from operations	22,530	(3,484)	65,886	12,102
Total assets	768,960	603,855	768,960	603,855	$ 610,592
Operating Segments [Member] | Transportation [Member]
Segment Reporting Information [Line Items]
Revenues	248,529	199,013	688,794	552,442
Income (loss) from operations	11,885	(7,641)	32,273	7,208
Total assets	456,638	288,917	456,638	288,917
Operating Segments [Member] | Logistics [Member]
Segment Reporting Information [Line Items]
Revenues	125,385	113,667	385,431	349,252
Income (loss) from operations	10,503	4,692	32,950	6,359
Total assets	292,054	287,649	292,054	287,649
Other [Member]
Segment Reporting Information [Line Items]
Revenues	378	321	1,105	948
Income (loss) from operations	142	(535)	663	(1,465)
Total assets	20,268	27,289	20,268	27,289
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenues	(3,594)	(2,398)	(10,271)	(7,149)
Intersegment Eliminations [Member] | Transportation [Member]
Segment Reporting Information [Line Items]
Revenues	(406)	(259)	(1,336)	(1,025)
Intersegment Eliminations [Member] | Logistics [Member]
Segment Reporting Information [Line Items]
Revenues	$ (3,188)	$ (2,139)	$ (8,935)	$ (6,124)