Business Segment Information - Net Revenues Calculation (Detail) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Segment Reporting [Abstract]
Total revenues		$ 1,854,262	$ 1,545,132
Expenses [Abstract]
Airfreight services		513,504	443,404
Ocean freight and ocean services		379,418	366,063
Customs brokerage and other services		325,502	208,060
Net revenues	[1]	$ 635,838	$ 527,605

[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.