Business Segment Information - Net Revenues Calculation (Detail) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Schedule of Net Revenues Calculation [Line Items]
Revenues	[1]	$ 2,035,579	$ 1,957,559	$ 4,055,630	$ 3,811,821
Expenses [Abstract]
Net revenues	[2]	661,695	642,546	1,315,809	1,278,384
Airfreight services
Schedule of Net Revenues Calculation [Line Items]
Revenues		741,577	801,761	1,456,478	1,532,988
Expenses [Abstract]
Direct Operating Costs		542,639	593,325	1,051,849	1,106,829
Ocean freight and ocean services
Schedule of Net Revenues Calculation [Line Items]
Revenues		543,809	530,008	1,112,450	1,050,891
Expenses [Abstract]
Direct Operating Costs		390,299	385,156	810,630	764,574
Customs brokerage and other services
Schedule of Net Revenues Calculation [Line Items]
Revenues		750,193	625,790	1,486,702	1,227,942
Expenses [Abstract]
Direct Operating Costs		$ 440,946	$ 336,532	$ 877,342	$ 662,034

[1] In 2019, the Company revised its process to record the transfer, between its geographic operating segments, of revenues and the directly related cost of transportation expenses for freight service transactions between Company origin and destination locations. This change better aligns revenue reporting with the location where the services are performed, as well as the transactional reporting being developed as part of the Company’s new accounting systems and processes. The change in presentation had no impact on consolidated or segment net revenues or operating income. The 2019 results also include the effect of changing the presentation of certain import services from a net to a gross basis, which increased segment revenues and directly related operating expenses but did not change net revenues. The impact of these changes on reported segment revenues was immaterial and prior year segment revenues have not been revised.

[2] Net revenues are a non-GAAP measure calculated as revenues less directly related operating expenses attributable to the Company's principal services. The Company's management believes that net revenues are a better measure than total revenues when evaluating the Company's operating segment performance since total revenues earned as a freight consolidator include the carriers' charges for carrying the shipment, whereas revenues earned in other capacities include primarily the commissions and fees earned by the Company. Net revenue is one of the Company's primary operational and financial measures and demonstrates the Company's ability to concentrate and leverage purchasing power through effective consolidation of shipments from customers utilizing a variety of transportation carriers and optimal routings.