Business Segment Information - Financial Information Regarding Company's Operations by Geographic Area (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014		Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Total revenues	$ 1,677,526		$ 1,491,645
Net revenues	529,486	[1]	464,586	[1]
Operating income	168,883		135,203
Identifiable assets at period end	2,943,778		2,925,504		2,890,905
Capital expenditures	9,445		8,760
Depreciation and amortization	11,529		12,382
Equity	1,927,531		1,960,014		1,871,608	2,086,331
United States Segment
Segment Reporting Information [Line Items]
Total revenues	444,181		400,739
Net revenues	219,603	[1]	192,082	[1]
Operating income	59,181		51,898
Identifiable assets at period end	1,451,103		1,437,768
Capital expenditures	6,325		3,928
Depreciation and amortization	7,393		7,852
Equity	1,182,808		1,151,455
Other North America Segment
Segment Reporting Information [Line Items]
Total revenues	54,794		51,584
Net revenues	30,678	[1]	26,161	[1]
Operating income	11,091		8,375
Identifiable assets at period end	109,180		105,070
Capital expenditures	288		264
Depreciation and amortization	292		280
Equity	58,998		69,702
Latin America Segment
Segment Reporting Information [Line Items]
Total revenues	24,081		20,629
Net revenues	16,559	[1]	15,357	[1]
Operating income	5,356		4,859
Identifiable assets at period end	57,232		61,503
Capital expenditures	617		301
Depreciation and amortization	268		212
Equity	34,604		32,017
North Asia Segment
Segment Reporting Information [Line Items]
Total revenues	645,444		568,689
Net revenues	117,405	[1]	93,394	[1]
Operating income	57,056		40,054
Identifiable assets at period end	541,983		545,148
Capital expenditures	290		2,660
Depreciation and amortization	1,399		1,502
Equity	306,775		333,871
South Asia Segment
Segment Reporting Information [Line Items]
Total revenues	181,381		140,743
Net revenues	42,200	[1]	39,093	[1]
Operating income	13,880		12,470
Identifiable assets at period end	143,910		151,184
Capital expenditures	319		456
Depreciation and amortization	530		596
Equity	106,139		112,090
Europe Segment
Segment Reporting Information [Line Items]
Total revenues	242,086		233,683
Net revenues	75,888	[1]	74,331	[1]
Operating income	15,071		11,642
Identifiable assets at period end	430,338		437,857
Capital expenditures	1,148		866
Depreciation and amortization	1,246		1,507
Equity	154,343		188,354
Middle East Africa And India Segment
Segment Reporting Information [Line Items]
Total revenues	85,559		75,578
Net revenues	27,153	[1]	24,168	[1]
Operating income	7,248		5,905
Identifiable assets at period end	198,954		183,288
Capital expenditures	458		285
Depreciation and amortization	401		433
Equity	120,086		108,009
Operating Segments | United States Segment
Segment Reporting Information [Line Items]
Total revenues	471,856		420,750
Operating Segments | Other North America Segment
Segment Reporting Information [Line Items]
Total revenues	57,608		53,959
Operating Segments | Latin America Segment
Segment Reporting Information [Line Items]
Total revenues	28,858		25,833
Operating Segments | North Asia Segment
Segment Reporting Information [Line Items]
Total revenues	651,141		574,106
Operating Segments | South Asia Segment
Segment Reporting Information [Line Items]
Total revenues	187,296		147,293
Operating Segments | Europe Segment
Segment Reporting Information [Line Items]
Total revenues	251,723		243,002
Operating Segments | Middle East Africa And India Segment
Segment Reporting Information [Line Items]
Total revenues	90,626		80,120
Intersegment Eliminations
Segment Reporting Information [Line Items]
Total revenues	(61,582)		(53,418)
Identifiable assets at period end	11,078		3,686
Equity	(36,222)		(35,484)
Intersegment Eliminations | United States Segment
Segment Reporting Information [Line Items]
Total revenues	(27,675)		(20,011)
Intersegment Eliminations | Other North America Segment
Segment Reporting Information [Line Items]
Total revenues	(2,814)		(2,375)
Intersegment Eliminations | Latin America Segment
Segment Reporting Information [Line Items]
Total revenues	(4,777)		(5,204)
Intersegment Eliminations | North Asia Segment
Segment Reporting Information [Line Items]
Total revenues	(5,697)		(5,417)
Intersegment Eliminations | South Asia Segment
Segment Reporting Information [Line Items]
Total revenues	(5,915)		(6,550)
Intersegment Eliminations | Europe Segment
Segment Reporting Information [Line Items]
Total revenues	(9,637)		(9,319)
Intersegment Eliminations | Middle East Africa And India Segment
Segment Reporting Information [Line Items]
Total revenues	$ (5,067)		$ (4,542)

[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.