Business Segment Information - Financial Information Regarding Company's Operations by Geographic Area (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013		Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Total revenues	$ 1,705,105		$ 1,537,966		$ 4,795,891		$ 4,454,398
Net revenues	513,256	[1]	484,902	[1]	1,462,556	[1]	1,404,781	[1]
Operating income	159,131		146,313		436,777		418,410
Identifiable assets at period end	2,926,053		3,098,563		2,926,053		3,098,563		3,014,812
Capital expenditures	8,255		15,482		26,650		42,691
Depreciation and amortization	12,741		12,629		37,540		35,581
Equity	1,903,930		2,180,730		1,903,930		2,180,730		2,086,331	2,032,570
United States Segment
Segment Reporting Information [Line Items]
Total revenues	438,882		396,764		1,256,075		1,166,633
Net revenues	215,320	[1]	199,107	[1]	607,508	[1]	572,959	[1]
Operating income	68,972		55,627		180,650		161,290
Identifiable assets at period end	1,333,124		1,694,366		1,333,124		1,694,366
Capital expenditures	3,171		12,463		12,646		22,196
Depreciation and amortization	8,369		7,608		24,100		21,641
Equity	1,074,837		1,423,598		1,074,837		1,423,598
Other North America Segment
Segment Reporting Information [Line Items]
Total revenues	55,209		52,962		162,136		161,317
Net revenues	27,323	[1]	26,255	[1]	79,017	[1]	75,476	[1]
Operating income	7,779		8,524		23,155		23,023
Identifiable assets at period end	113,621		102,713		113,621		102,713
Capital expenditures	361		639		1,047		1,534
Depreciation and amortization	303		211		879		615
Equity	75,848		63,351		75,848		63,351
Latin America Segment
Segment Reporting Information [Line Items]
Total revenues	22,962		22,136		65,594		63,421
Net revenues	16,792	[1]	15,627	[1]	48,797	[1]	45,560	[1]
Operating income	4,890		5,317		14,425		14,007
Identifiable assets at period end	53,939		52,785		53,939		52,785
Capital expenditures	369		147		841		551
Depreciation and amortization	226		210		665		680
Equity	34,218		30,637		34,218		30,637
Asia Pacific Segment
Segment Reporting Information [Line Items]
Total revenues	850,855		777,845		2,346,073		2,221,264
Net revenues	149,069	[1]	147,477	[1]	420,788	[1]	424,466	[1]
Operating income	57,409		57,975		161,686		165,640
Identifiable assets at period end	733,776		663,584		733,776		663,584
Capital expenditures	2,942		1,250		7,975		14,858
Depreciation and amortization	2,030		2,343		6,246		6,314
Equity	454,982		439,719		454,982		439,719
Europe And Africa Segment
Segment Reporting Information [Line Items]
Total revenues	253,683		212,507		725,833		621,040
Net revenues	79,007	[1]	70,949	[1]	230,702	[1]	212,631	[1]
Operating income	14,413		11,894		39,698		35,433
Identifiable assets at period end	506,442		438,711		506,442		438,711
Capital expenditures	1,042		703		3,156		2,464
Depreciation and amortization	1,389		1,534		4,352		4,713
Equity	199,751		181,134		199,751		181,134
Middle East And India Segment
Segment Reporting Information [Line Items]
Total revenues	83,514		75,752		240,180		220,723
Net revenues	25,745	[1]	25,487	[1]	75,744	[1]	73,689	[1]
Operating income	5,668		6,976		17,163		19,017
Identifiable assets at period end	173,455		142,843		173,455		142,843
Capital expenditures	370		280		985		1,088
Depreciation and amortization	424		723		1,298		1,618
Equity	97,476		75,444		97,476		75,444
Operating Segments | United States Segment
Segment Reporting Information [Line Items]
Total revenues	463,729		418,829		1,323,341		1,231,941
Operating Segments | Other North America Segment
Segment Reporting Information [Line Items]
Total revenues	58,076		55,873		169,965		169,288
Operating Segments | Latin America Segment
Segment Reporting Information [Line Items]
Total revenues	28,156		27,779		81,559		79,554
Operating Segments | Asia Pacific Segment
Segment Reporting Information [Line Items]
Total revenues	863,820		789,926		2,383,440		2,255,580
Operating Segments | Europe And Africa Segment
Segment Reporting Information [Line Items]
Total revenues	263,175		221,865		753,750		648,467
Operating Segments | Middle East And India Segment
Segment Reporting Information [Line Items]
Total revenues	88,941		80,225		255,707		234,082
Intersegment Eliminations
Segment Reporting Information [Line Items]
Total revenues	(60,792)		(56,531)		(171,871)		(164,514)
Identifiable assets at period end	11,696		3,561		11,696		3,561
Equity	(33,182)		(33,153)		(33,182)		(33,153)
Intersegment Eliminations | United States Segment
Segment Reporting Information [Line Items]
Total revenues	(24,847)		(22,065)		(67,266)		(65,308)
Intersegment Eliminations | Other North America Segment
Segment Reporting Information [Line Items]
Total revenues	(2,867)		(2,911)		(7,829)		(7,971)
Intersegment Eliminations | Latin America Segment
Segment Reporting Information [Line Items]
Total revenues	(5,194)		(5,643)		(15,965)		(16,133)
Intersegment Eliminations | Asia Pacific Segment
Segment Reporting Information [Line Items]
Total revenues	(12,965)		(12,081)		(37,367)		(34,316)
Intersegment Eliminations | Europe And Africa Segment
Segment Reporting Information [Line Items]
Total revenues	(9,492)		(9,358)		(27,917)		(27,427)
Intersegment Eliminations | Middle East And India Segment
Segment Reporting Information [Line Items]
Total revenues	$ (5,427)		$ (4,473)		$ (15,527)		$ (13,359)

[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.