Financial Information Regarding Company's Operations by Geographic Area (Detail) (USD $) In Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010	Dec. 31, 2009
Segment Reporting Information [Line Items]
Revenues from unaffiliated customers	$ 1,581,368	$ 1,516,770	$ 3,042,216	$ 2,717,879
Transfers between geographic areas	0	0		0
Total revenues	1,581,368	1,516,770	3,042,216	2,717,879
Net revenues	472,561	418,858	926,476	780,681
Operating income	152,275	138,496	299,505	239,037
Identifiable assets at quarter end	2,878,004	2,546,542	2,878,004	2,546,542	2,679,179
Capital expenditures	17,110	8,118	38,235	15,700
Depreciation and amortization	9,257	9,110	18,431	18,505
Equity	1,879,150	1,634,808	1,879,150	1,634,808	1,748,154	1,561,347
United States
Segment Reporting Information [Line Items]
Revenues from unaffiliated customers	390,806	331,619	767,911	618,555
Transfers between geographic areas	25,973	25,429	49,938	44,172
Total revenues	416,779	357,048	817,849	662,727
Net revenues	181,603	163,036	359,537	309,941
Operating income	57,752	52,516	111,486	90,690
Identifiable assets at quarter end	1,411,881	1,324,522	1,411,881	1,324,522
Capital expenditures	3,350	3,366	7,380	7,840
Depreciation and amortization	4,926	4,848	9,911	9,870
Equity	1,123,482	1,047,968	1,123,482	1,047,968
Other North America
Segment Reporting Information [Line Items]
Revenues from unaffiliated customers	47,816	41,675	91,663	77,287
Transfers between geographic areas	2,783	2,346	5,465	4,155
Total revenues	50,599	44,021	97,128	81,442
Net revenues	21,581	19,424	42,282	35,846
Operating income	5,761	5,572	11,550	9,471
Identifiable assets at quarter end	91,678	85,645	91,678	85,645
Capital expenditures	448	149	608	325
Depreciation and amortization	277	353	580	706
Equity	52,814	46,978	52,814	46,978
Latin America
Segment Reporting Information [Line Items]
Revenues from unaffiliated customers	21,136	18,621	41,469	34,917
Transfers between geographic areas	5,220	4,231	10,841	7,892
Total revenues	26,356	22,852	52,310	42,809
Net revenues	15,157	12,729	30,260	24,247
Operating income	4,486	3,787	9,249	7,318
Identifiable assets at quarter end	58,396	46,951	58,396	46,951
Capital expenditures	144	357	300	634
Depreciation and amortization	264	211	533	416
Equity	33,784	22,232	33,784	22,232
Asia Pacific
Segment Reporting Information [Line Items]
Revenues from unaffiliated customers	816,350	876,070	1,544,480	1,513,258
Transfers between geographic areas	10,170	8,158	19,353	15,268
Total revenues	826,520	884,228	1,563,833	1,528,526
Net revenues	150,616	137,328	292,104	244,437
Operating income	61,542	56,134	120,980	94,892
Identifiable assets at quarter end	678,668	553,173	678,668	553,173
Capital expenditures	4,622	1,424	9,334	2,114
Depreciation and amortization	1,847	1,861	3,816	3,757
Equity	420,962	338,102	420,962	338,102
Europe And Africa
Segment Reporting Information [Line Items]
Revenues from unaffiliated customers	229,724	172,869	443,335	334,714
Transfers between geographic areas	11,355	10,429	22,062	18,362
Total revenues	241,079	183,298	465,397	353,076
Net revenues	78,828	64,054	152,753	123,977
Operating income	16,877	14,888	34,584	26,742
Identifiable assets at quarter end	479,852	394,430	479,852	394,430
Capital expenditures	7,881	2,231	19,587	3,452
Depreciation and amortization	1,416	1,225	2,526	2,537
Equity	184,252	134,216	184,252	134,216
Middle East And India
Segment Reporting Information [Line Items]
Revenues from unaffiliated customers	75,536	75,916	153,358	139,148
Transfers between geographic areas	4,500	3,894	8,709	7,470
Total revenues	80,036	79,810	162,067	146,618
Net revenues	24,776	22,287	49,540	42,233
Operating income	5,857	5,599	11,656	9,924
Identifiable assets at quarter end	155,503	134,715	155,503	134,715
Capital expenditures	665	591	1,026	1,335
Depreciation and amortization	527	612	1,065	1,219
Equity	94,447	77,541	94,447	77,541
Eliminations
Segment Reporting Information [Line Items]
Transfers between geographic areas	(60,001)	(54,487)	(116,368)	(97,319)
Total revenues	(60,001)	(54,487)	(116,368)	(97,319)
Identifiable assets at quarter end	2,026	7,106	2,026	7,106
Equity	$ (30,591)	$ (32,229)	$ (30,591)	$ (32,229)