Summary of Revenue by Segment and Business Line (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Segment Reporting Information [Line Items]
Revenue	$ 1,095,971	$ 892,756
Intermodal [Member]
Segment Reporting Information [Line Items]
Revenue	600,998	531,367
Truck brokerage [Member]
Segment Reporting Information [Line Items]
Revenue	220,382	183,961
Logistics [Member]
Segment Reporting Information [Line Items]
Revenue	214,211	177,428
Dedicated [Member]
Segment Reporting Information [Line Items]
Revenue	60,380
Operating Segments [Member] | Hub [Member]
Segment Reporting Information [Line Items]
Revenue	831,585	676,480
Operating Segments [Member] | Mode LLC [Member]
Segment Reporting Information [Line Items]
Revenue	287,899	241,834
Operating Segments [Member] | Intermodal [Member] | Hub [Member]
Segment Reporting Information [Line Items]
Revenue	482,495	424,423
Operating Segments [Member] | Intermodal [Member] | Mode LLC [Member]
Segment Reporting Information [Line Items]
Revenue	129,773	122,181
Operating Segments [Member] | Truck brokerage [Member] | Hub [Member]
Segment Reporting Information [Line Items]
Revenue	120,019	106,185
Operating Segments [Member] | Truck brokerage [Member] | Mode LLC [Member]
Segment Reporting Information [Line Items]
Revenue	100,721	78,161
Operating Segments [Member] | Logistics [Member] | Hub [Member]
Segment Reporting Information [Line Items]
Revenue	168,676	145,872
Operating Segments [Member] | Logistics [Member] | Mode LLC [Member]
Segment Reporting Information [Line Items]
Revenue	57,405	41,492
Operating Segments [Member] | Dedicated [Member] | Hub [Member]
Segment Reporting Information [Line Items]
Revenue	60,395
Intersegment Elims [Member]
Segment Reporting Information [Line Items]
Revenue	(23,513)	(25,558)
Intersegment Elims [Member] | Intermodal [Member]
Segment Reporting Information [Line Items]
Revenue	(11,270)	(15,237)
Intersegment Elims [Member] | Truck brokerage [Member]
Segment Reporting Information [Line Items]
Revenue	(358)	(385)
Intersegment Elims [Member] | Logistics [Member]
Segment Reporting Information [Line Items]
Revenue	(11,870)	$ (9,936)
Intersegment Elims [Member] | Dedicated [Member]
Segment Reporting Information [Line Items]
Revenue	$ (15)