Business Segment Information - Financial Information Regarding Company's Operations by Geographic Area (Detail) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015		Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Segment Reporting Information [Line Items]
Total revenues		$ 1,596,221	$ 1,651,332	$ 1,691,553	$ 1,677,526	$ 1,768,830	$ 1,705,105	$ 1,599,141	$ 1,491,645	$ 6,616,632		$ 6,564,721		$ 6,080,257
Net revenues		536,169	$ 569,981	$ 552,141	$ 529,486	518,871	$ 513,256	$ 484,714	$ 464,586	2,187,777	[1]	1,981,427	[1]	1,882,853	[1]
Operating income										721,484		594,648		552,073
Identifiable assets at year end		2,582,438				2,890,905				2,582,438		2,890,905		3,014,812
Capital expenditures										44,383		37,472		53,411
Depreciation and amortization										46,012		49,292		48,071
Equity		1,694,676				1,871,608				1,694,676		1,871,608		2,086,331		$ 2,032,570
United States Segment
Segment Reporting Information [Line Items]
Total revenues										1,763,361		1,694,819		1,561,468
Other North America Segment
Segment Reporting Information [Line Items]
Total revenues										226,284		218,735		215,968
Latin America Segment
Segment Reporting Information [Line Items]
Total revenues										94,229		89,058		86,050
North Asia Segment
Segment Reporting Information [Line Items]
Total revenues										2,557,398		2,576,350		2,444,331
South Asia Segment
Segment Reporting Information [Line Items]
Total revenues										677,628		657,189		601,708
Europe Segment
Segment Reporting Information [Line Items]
Total revenues										958,827		1,012,389		876,967
Middle East Africa And India Segment
Segment Reporting Information [Line Items]
Total revenues										338,905		316,181		293,765
Geography Eliminations | United States Segment
Segment Reporting Information [Line Items]
Total revenues										(118,884)		(97,028)		(89,570)
Geography Eliminations | Other North America Segment
Segment Reporting Information [Line Items]
Total revenues										(13,383)		(10,891)		(11,038)
Geography Eliminations | Latin America Segment
Segment Reporting Information [Line Items]
Total revenues										(19,158)		(20,634)		(21,711)
Geography Eliminations | North Asia Segment
Segment Reporting Information [Line Items]
Total revenues										(21,722)		(23,020)		(22,505)
Geography Eliminations | South Asia Segment
Segment Reporting Information [Line Items]
Total revenues										(25,018)		(26,579)		(24,073)
Geography Eliminations | Europe Segment
Segment Reporting Information [Line Items]
Total revenues										(42,787)		(39,541)		(38,728)
Geography Eliminations | Middle East Africa And India Segment
Segment Reporting Information [Line Items]
Total revenues										(21,322)		(19,654)		(16,698)
Operating Segments | United States Segment
Segment Reporting Information [Line Items]
Total revenues										1,882,245		1,791,847		1,651,038
Net revenues	[1]									906,780		823,111		770,519
Operating income										245,257		221,166		195,799
Identifiable assets at year end		1,202,532				1,408,598				1,202,532		1,408,598		1,582,557
Capital expenditures										26,807		19,610		28,699
Depreciation and amortization										29,532		31,553		29,569
Equity		986,330				1,165,488				986,330		1,165,488		1,330,262
Operating Segments | Other North America Segment
Segment Reporting Information [Line Items]
Total revenues										239,667		229,626		227,006
Net revenues	[1]									124,381		108,631		102,864
Operating income										46,846		36,475		35,224
Identifiable assets at year end		111,549				111,324				111,549		111,324		104,735
Capital expenditures										3,915		1,439		1,870
Depreciation and amortization										1,331		1,170		882
Equity		70,932				54,338				70,932		54,338		72,772
Operating Segments | Latin America Segment
Segment Reporting Information [Line Items]
Total revenues										113,387		109,692		107,761
Net revenues	[1]									65,017		65,016		61,478
Operating income										19,656		19,855		15,734
Identifiable assets at year end		48,678				53,815				48,678		53,815		58,027
Capital expenditures										1,756		1,574		1,010
Depreciation and amortization										1,041		911		901
Equity		33,161				34,386				33,161		34,386		29,590
Operating Segments | North Asia Segment
Segment Reporting Information [Line Items]
Total revenues										2,579,120		2,599,370		2,466,836
Net revenues	[1]									493,235		407,410		396,395
Operating income										245,854		177,496		169,252
Identifiable assets at year end		446,914				513,649				446,914		513,649		527,859
Capital expenditures										2,203		5,955		15,344
Depreciation and amortization										5,425		5,938		6,078
Equity		253,097				262,295				253,097		262,295		305,883
Operating Segments | South Asia Segment
Segment Reporting Information [Line Items]
Total revenues										702,646		683,768		625,781
Net revenues	[1]									179,110		163,383		164,505
Operating income										69,643		52,596		54,728
Identifiable assets at year end		127,014				141,499				127,014		141,499		140,173
Capital expenditures										2,383		3,118		1,887
Depreciation and amortization										2,110		2,295		2,303
Equity		99,220				99,234				99,220		99,234		100,845
Operating Segments | Europe Segment
Segment Reporting Information [Line Items]
Total revenues										1,001,614		1,051,930		915,695
Net revenues	[1]									308,301		313,325		288,407
Operating income										65,024		62,101		53,294
Identifiable assets at year end		421,590				447,349				421,590		447,349		414,710
Capital expenditures										5,222		4,246		3,313
Depreciation and amortization										4,931		5,690		6,569
Equity		154,174				169,117				154,174		169,117		178,729
Operating Segments | Middle East Africa And India Segment
Segment Reporting Information [Line Items]
Total revenues										360,227		335,835		310,463
Net revenues	[1]									110,953		100,551		98,685
Operating income										29,204		24,959		28,042
Identifiable assets at year end		221,835				208,684				221,835		208,684		180,646
Capital expenditures										2,097		1,530		1,288
Depreciation and amortization										1,642		1,735		1,769
Equity		130,105				121,520				130,105		121,520		102,628
Intersegment Eliminations
Segment Reporting Information [Line Items]
Total revenues										(262,274)		(237,347)		(224,323)
Identifiable assets at year end		2,326				5,987				2,326		5,987		6,105
Equity		$ (32,343)				$ (34,770)				$ (32,343)		$ (34,770)		$ (34,378)

[1] Net revenues are a non-GAAP measure calculated as revenues less directly related operations 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.