Business Segment Information - Net Revenues Calculation (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Segment Reporting [Abstract]
Total revenues		$ 1,802,166	$ 1,562,394	$ 5,019,577	$ 4,456,030
Expenses [Abstract]
Airfreight services		547,595	444,359	1,490,417	1,236,555
Ocean freight and ocean services		411,061	359,991	1,163,051	1,006,710
Customs brokerage and other services		244,368	212,785	675,729	597,320
Net revenues	[1]	$ 599,142	$ 545,259	$ 1,690,380	$ 1,615,445

[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.