Business Segment Information Business Segment Information - Net Revenues Calculation (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018		Dec. 31, 2017		Dec. 31, 2016
Schedule of Net Revenues Calculation [Line Items]
Total revenues	$ 2,235,597	$ 2,090,947	$ 1,957,559	$ 1,854,262	$ 1,901,371	$ 1,802,166	$ 1,672,279	$ 1,545,132	$ 8,138,365		$ 6,920,948		$ 6,098,037
Net revenues	$ 680,675	$ 661,314	$ 642,546	$ 635,838	$ 628,809	$ 599,142	$ 563,633	$ 527,605	2,620,373	[1]	2,319,189	[1]	2,164,036	[1]
Airfreight services
Schedule of Net Revenues Calculation [Line Items]
Total revenues									3,271,932		2,877,032		2,453,347
Direct Operating Costs									2,410,793		2,126,761		1,752,167
Ocean freight and ocean services
Schedule of Net Revenues Calculation [Line Items]
Total revenues									2,251,754		2,107,045		1,917,494
Direct Operating Costs									1,664,168		1,543,740		1,378,699
Customs brokerage and other services
Schedule of Net Revenues Calculation [Line Items]
Total revenues									2,614,679		1,936,871		1,727,196
Direct Operating Costs									$ 1,443,031		$ 931,258		$ 803,135

[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.