Business Segment Information - Financial Information Regarding Company's Operations by Geographic Area (Detail) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Total revenues		$ 1,475,164	$ 1,691,553	$ 2,893,636	$ 3,369,079
Net revenues	[1]	553,117	552,141	1,070,186	1,081,627
Operating income		178,864	182,716	330,690	351,599
Identifiable assets at period end		2,707,138	2,932,375	2,707,138	2,932,375	$ 2,582,438
Capital expenditures		13,279	12,912	27,314	22,357
Depreciation and amortization		11,642	11,420	22,971	22,949
Equity		1,779,505	1,889,733	1,779,505	1,889,733	$ 1,694,676	$ 1,871,608
United States Segment
Segment Reporting Information [Line Items]
Total revenues		417,735	449,622	825,561	893,803
Other North America Segment
Segment Reporting Information [Line Items]
Total revenues		56,674	58,739	108,780	113,533
Latin America Segment
Segment Reporting Information [Line Items]
Total revenues		21,169	24,314	41,233	48,395
North Asia Segment
Segment Reporting Information [Line Items]
Total revenues		517,489	649,901	1,014,721	1,295,345
South Asia Segment
Segment Reporting Information [Line Items]
Total revenues		151,890	184,862	288,308	366,243
Europe Segment
Segment Reporting Information [Line Items]
Total revenues		229,882	239,953	451,779	482,039
Middle East Africa And India Segment
Segment Reporting Information [Line Items]
Total revenues		80,325	84,162	163,254	169,721
Geography Eliminations | United States Segment
Segment Reporting Information [Line Items]
Total revenues		28,973	32,486	55,007	60,161
Geography Eliminations | Other North America Segment
Segment Reporting Information [Line Items]
Total revenues		2,671	3,685	5,371	6,499
Geography Eliminations | Latin America Segment
Segment Reporting Information [Line Items]
Total revenues		4,187	5,403	7,788	10,180
Geography Eliminations | North Asia Segment
Segment Reporting Information [Line Items]
Total revenues		5,385	5,427	10,481	11,124
Geography Eliminations | South Asia Segment
Segment Reporting Information [Line Items]
Total revenues		6,326	6,473	12,132	12,388
Geography Eliminations | Europe Segment
Segment Reporting Information [Line Items]
Total revenues		10,097	10,716	20,458	20,353
Geography Eliminations | Middle East Africa And India Segment
Segment Reporting Information [Line Items]
Total revenues		5,507	5,112	10,901	10,179
Operating Segments | United States Segment
Segment Reporting Information [Line Items]
Total revenues		446,708	482,108	880,568	953,964
Net revenues	[1]	232,860	229,353	453,558	448,956
Operating income		67,214	68,547	115,419	127,728
Identifiable assets at period end		1,363,352	1,381,755	1,363,352	1,381,755
Capital expenditures		8,778	7,711	16,915	14,036
Depreciation and amortization		7,366	7,339	14,698	14,732
Equity		1,069,876	1,075,703	1,069,876	1,075,703
Operating Segments | Other North America Segment
Segment Reporting Information [Line Items]
Total revenues		59,345	62,424	114,151	120,032
Net revenues	[1]	30,815	30,576	58,193	61,254
Operating income		9,600	10,437	16,891	21,528
Identifiable assets at period end		84,358	103,613	84,358	103,613
Capital expenditures		445	1,656	756	1,944
Depreciation and amortization		380	310	744	602
Equity		38,638	59,374	38,638	59,374
Operating Segments | Latin America Segment
Segment Reporting Information [Line Items]
Total revenues		25,356	29,717	49,021	58,575
Net revenues	[1]	14,468	17,485	28,201	34,044
Operating income		3,836	5,441	7,688	10,797
Identifiable assets at period end		58,570	57,711	58,570	57,711
Capital expenditures		317	569	802	1,186
Depreciation and amortization		288	248	541	516
Equity		39,482	38,447	39,482	38,447
Operating Segments | North Asia Segment
Segment Reporting Information [Line Items]
Total revenues		522,874	655,328	1,025,202	1,306,469
Net revenues	[1]	122,117	124,491	232,908	241,896
Operating income		61,721	60,597	116,939	117,653
Identifiable assets at period end		471,832	572,425	471,832	572,425
Capital expenditures		678	475	1,763	765
Depreciation and amortization		1,388	1,379	2,707	2,778
Equity		309,557	344,479	309,557	344,479
Operating Segments | South Asia Segment
Segment Reporting Information [Line Items]
Total revenues		158,216	191,335	300,440	378,631
Net revenues	[1]	46,257	46,944	85,775	89,144
Operating income		18,354	16,140	34,045	30,020
Identifiable assets at period end		118,352	141,344	118,352	141,344
Capital expenditures		351	989	1,006	1,308
Depreciation and amortization		543	548	1,055	1,078
Equity		78,668	118,175	78,668	118,175
Operating Segments | Europe Segment
Segment Reporting Information [Line Items]
Total revenues		239,979	250,669	472,237	502,392
Net revenues	[1]	77,639	76,607	152,180	152,495
Operating income		11,838	15,587	24,091	30,658
Identifiable assets at period end		378,859	448,475	378,859	448,475
Capital expenditures		2,140	921	4,259	2,069
Depreciation and amortization		1,188	1,176	2,286	2,422
Equity		133,387	166,569	133,387	166,569
Operating Segments | Middle East Africa And India Segment
Segment Reporting Information [Line Items]
Total revenues		85,832	89,274	174,155	179,900
Net revenues	[1]	28,975	26,685	59,382	53,838
Operating income		6,315	5,967	15,628	13,215
Identifiable assets at period end		225,877	219,280	225,877	219,280
Capital expenditures		570	591	1,813	1,049
Depreciation and amortization		489	420	940	821
Equity		141,315	124,564	141,315	124,564
Intersegment Eliminations
Segment Reporting Information [Line Items]
Total revenues		(63,146)	(69,302)	(122,138)	(130,884)
Net revenues	[1]	(14)		(11)
Operating income		(14)		(11)
Identifiable assets at period end		5,938	7,772	5,938	7,772
Equity		$ (31,418)	$ (37,578)	$ (31,418)	$ (37,578)

[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.