Business Segment Information - Financial Information Regarding Company's Operations by Geographic Area (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012		Dec. 31, 2012	Dec. 31, 2011
Segment Reporting Information [Line Items]
Total revenues	$ 1,500,453		$ 1,504,952		$ 2,910,938		$ 2,916,322
Net revenues	469,101	[1]	453,651	[1]	914,385	[1]	900,222	[1]
Operating income	143,579		132,403		272,097		257,674
Identifiable assets at period end	3,063,665		2,992,372		3,063,665		2,992,372		2,954,125
Capital expenditures	17,141		9,814		27,209		26,902
Depreciation and amortization	11,674		9,670		22,952		19,215
Equity	2,121,942		2,050,057		2,121,942		2,050,057		2,032,570	2,010,069
United States Segment
Segment Reporting Information [Line Items]
Total revenues	392,804		379,126		764,523		756,428
Net revenues	190,818	[1]	182,291	[1]	368,506	[1]	363,766	[1]
Operating income	58,310		49,193		105,663		94,718
Identifiable assets at period end	1,531,739		1,597,543		1,531,739		1,597,543
Capital expenditures	4,354		5,236		9,733		14,995
Depreciation and amortization	7,276		5,756		14,033		11,378
Equity	1,209,762		1,295,963		1,209,762		1,295,963
Other North America Segment
Segment Reporting Information [Line Items]
Total revenues	56,626		49,802		108,355		99,756
Net revenues	25,440	[1]	25,115	[1]	49,221	[1]	47,357	[1]
Operating income	7,887		8,085		14,499		14,454
Identifiable assets at period end	101,721		93,374		101,721		93,374
Capital expenditures	708		153		895		329
Depreciation and amortization	197		181		404		368
Equity	65,897		51,248		65,897		51,248
Latin America Segment
Segment Reporting Information [Line Items]
Total revenues	21,421		21,366		41,285		40,635
Net revenues	15,522	[1]	14,724	[1]	29,933	[1]	29,559	[1]
Operating income	4,601		4,118		8,690		8,880
Identifiable assets at period end	53,795		52,019		53,795		52,019
Capital expenditures	145		400		404		655
Depreciation and amortization	229		207		470		424
Equity	33,272		31,903		33,272		31,903
Asia Pacific Segment
Segment Reporting Information [Line Items]
Total revenues	749,227		780,858		1,443,322		1,468,928
Net revenues	141,385	[1]	135,908	[1]	276,892	[1]	267,722	[1]
Operating income	54,781		51,768		107,665		99,006
Identifiable assets at period end	809,827		687,586		809,827		687,586
Capital expenditures	11,056		2,602		13,608		7,889
Depreciation and amortization	1,983		1,645		3,971		3,269
Equity	606,793		462,123		606,793		462,123
Europe And Africa Segment
Segment Reporting Information [Line Items]
Total revenues	205,995		202,301		408,482		408,572
Net revenues	71,042	[1]	71,497	[1]	141,631	[1]	143,030	[1]
Operating income	11,613		12,951		23,539		27,198
Identifiable assets at period end	418,077		412,752		418,077		412,752
Capital expenditures	563		1,111		1,761		2,053
Depreciation and amortization	1,550		1,430		3,179		2,834
Equity	166,891		144,659		166,891		144,659
Middle East And India Segment
Segment Reporting Information [Line Items]
Total revenues	74,380		71,499		144,971		142,003
Net revenues	24,894	[1]	24,116	[1]	48,202	[1]	48,788	[1]
Operating income	6,387		6,288		12,041		13,418
Identifiable assets at period end	155,058		152,754		155,058		152,754
Capital expenditures	315		312		808		981
Depreciation and amortization	439		451		895		942
Equity	75,418		94,892		75,418		94,892
Operating Segments | United States Segment
Segment Reporting Information [Line Items]
Total revenues	416,021		401,630		807,766		801,140
Operating Segments | Other North America Segment
Segment Reporting Information [Line Items]
Total revenues	59,142		52,268		113,415		104,687
Operating Segments | Latin America Segment
Segment Reporting Information [Line Items]
Total revenues	27,035		26,157		51,775		50,505
Operating Segments | Asia Pacific Segment
Segment Reporting Information [Line Items]
Total revenues	760,832		791,896		1,465,557		1,490,938
Operating Segments | Europe And Africa Segment
Segment Reporting Information [Line Items]
Total revenues	215,184		211,904		426,551		427,642
Operating Segments | Middle East And India Segment
Segment Reporting Information [Line Items]
Total revenues	78,939		76,169		153,857		151,324
Intersegment Eliminations
Segment Reporting Information [Line Items]
Total revenues	(56,700)		(55,072)		(107,983)		(109,914)
Identifiable assets at period end	(6,552)		(3,656)		(6,552)		(3,656)
Equity	(36,091)		(30,731)		(36,091)		(30,731)
Intersegment Eliminations | United States Segment
Segment Reporting Information [Line Items]
Total revenues	(23,217)		(22,504)		(43,243)		(44,712)
Intersegment Eliminations | Other North America Segment
Segment Reporting Information [Line Items]
Total revenues	(2,516)		(2,466)		(5,060)		(4,931)
Intersegment Eliminations | Latin America Segment
Segment Reporting Information [Line Items]
Total revenues	(5,614)		(4,791)		(10,490)		(9,870)
Intersegment Eliminations | Asia Pacific Segment
Segment Reporting Information [Line Items]
Total revenues	(11,605)		(11,038)		(22,235)		(22,010)
Intersegment Eliminations | Europe And Africa Segment
Segment Reporting Information [Line Items]
Total revenues	(9,189)		(9,603)		(18,069)		(19,070)
Intersegment Eliminations | Middle East And India Segment
Segment Reporting Information [Line Items]
Total revenues	$ (4,559)		$ (4,670)		$ (8,886)		$ (9,321)

[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 are total revenues when evaluating the Company's operating segment performance since total revenues earned as a freight consolidator must consider 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 (buy rates) through effective consolidation of shipments from customers utilizing a variety of transportation carriers and optimal routings.