Business Segment Information - Net Revenues Calculation (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Schedule of Net Revenues Calculation [Line Items]
Total revenues		$ 2,090,947	$ 1,802,166	$ 5,902,768	$ 5,019,577
Expenses [Abstract]
Net revenues	[1]	661,314	599,142	1,939,698	1,690,380
Airfreight services
Schedule of Net Revenues Calculation [Line Items]
Total revenues		833,338	735,164	2,366,326	2,022,577
Expenses [Abstract]
Direct Operating Costs		620,554	547,595	1,727,383	1,490,417
Ocean freight and ocean services
Schedule of Net Revenues Calculation [Line Items]
Total revenues		585,810	563,386	1,636,701	1,585,730
Expenses [Abstract]
Direct Operating Costs		435,313	411,061	1,199,887	1,163,051
Customs brokerage and other services
Schedule of Net Revenues Calculation [Line Items]
Total revenues		671,799	503,616	1,899,741	1,411,270
Expenses [Abstract]
Direct Operating Costs		$ 373,766	$ 244,368	$ 1,035,800	$ 675,729

[1] 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.